United States

Images taken in United States

Remove Filters: R.J. Reynolds Tobacco Company Slide Set^(X) 5 Sizes Available^(X)

271 Images of 89 Subjects

View Image Details

Image	Subject Name	Scientific Name	Description
1440133	stilt bug	Jalysus wickhami	Spined stilt bugs are slender brown bugs about 1/2 inch in length when full grown. They have long thread-like legs and antennae. Nymphs are similar to the adults but are smaller, lighter in color, and wingless. Stilt bugs are commonly seen walking slowly over tobacco plants or flying about the field in search of prey. These important beneficials feed on hornworm and budworm eggs (and to some extent on aphids) and may have a major impact on reducing damage caused by these pests.
1440043	Pythium diseases	Pythium spp.	Stem rot occurs on tobacco transplants shortly after they are set in the field. Stem rot may begin in the plant bed and be moved to the field on infected transplants, or it may begin after plants are set in the field. The development of stem rot is sporadic, being favored by wet weather and injured plants. Under favorable conditions, Pythium attacks the stems of newly set plants causing brown, watery lesions to develop near the soil line. As the fungus disease develops, stem tissue collapse and disintegrate, causing death of the plant. Stem rot usually appears as a watery soft rot; a cottony fungus mass may be present. Stem rot may be confused with sore shin or black shank, thus requiring microscopic examination for confirmation.
1440089	phosphorous deficiency		Tobacco deficient in P will be slow-growing, stunted, late maturing, and display a dark to very dark green color throughout the plant. Leaves tend to be more erect, closer together, shorter, and narrower than those receiving ample P. Temporary symptoms that have been reported as indicating P deficiencies include plants wilting during mid-day and occurrence on lower leaves of brown (dead) spots that are sometimes surrounded by a pale yellowish-green color. P deficiency symptoms are perhaps less evident and more difficult to recognize in the field than symptoms produced by deficiencies of any other essential plant nutrients. Therefore, soil and/or plant analyses are often necessary to verify suspected P deficiencies.
1440090	potassium deficiency		Symptoms of K deficiency in tobacco first appear on lower or middle leaves and move up the plant as the problem becomes more severe. The distinguishing characteristic is mottled or "scorched" appearance that develops at the tips and along the edges of leaves. In the early stages, mottles are pale green or yellow, followed by the development of brown or dead centers. As the deficiency increases, mottles tend to run together and the dead areas fall out resulting in ragged leaf margins. Because the remaining green areas continue to grow, leaves often develop a crumpled or puckered appearance with edges cupping downward. K deficiencies appear to be encouraged by dry weather. Also, tobacco is usually less stunted by a deficiency of K than by a deficiency of either N or P.
1440101	tobacco wireworm	Conoderus vespertinus	Wireworms (various species) are the major soil insects attacking tobacco. The yellow to brown, hard-bodied larvae are slender and cylindrical. The adult is a click beetle. Wireworms hatch in the summer, spend the winter in the soil and are usually most destructive to newly transplanted tobacco. Wireworm larvae cut off small underground stems and roots and bore into larger stems and roots. They may be found tunneling in stems near the soil surface . Affected plants may become stunted or wilt and die within a few days. Tobacco following sod may be damaged by wireworms for one to five years because some species have long life cycles.
1440088	nitrogen deficiency		The most easily observed symptom of N deficient tobacco is the yellowing (chlorosis) of the leaves due to reduced chlorophyll levels. The yellowing begins in the lower leaves and moves upward as the deficiency increases. Under severe deficiencies, the entire plant will show a decrease in normal green color with bottom leaves changing from a light yellow to a brown or dead appearance. This drying-up or "firing" appearance may also result from water shortages during drought conditions. N deficient plants are usually normal in shape but less than normal in size. Leaves are generally smaller, thinner, and more upright on the stalk than when N is adequate. Waterlogged or flooded soils and turning under of thick stands of non-leguminous crops or sods without sufficient time for decomposition are conditions often associated with N deficiencies.
1440086	chemicals		Fatty alcohols (contact sucker control chemicals) turn small suckers brown shortly after application. Leaf axils may be burned by high concentrations of these alcohols. Buds of young plants may be killed. Leaf burn may be observed, particularly along the outer edge of tender upper leaves. Damage from these burns is usually minor, but it can be severe if the concentration of the chemical is excessive or the application is made to wilted plants. Leaf drop, shown in above photo, may occur at the bottom of the plant if the leaf axils have been severely burned.
1440047	black root rot	Thielaviopsis basicola	Uneven growth of tobacco in the field is indicative of black root rot. Affected plants often become yellowed and are smaller than neighboring healthy plants. Stunting is more evident during the early part of the growing season and during cool, wet seasons. On hot days, leaves of the diseased plants wilt more rapidly than those of healthy plants, but recover during the night. Plants usually grow out of the problem as soil temperatures rise, unless the variety is highly susceptible to the fungus and cool, wet soil conditions prevail. the most distinctive symptoms of black root rot occur on the roots. The entire root system is greatly reduced with smaller roots exhibiting a typical brown to black discoloration of their tips, and larger roots having brown or black spots on their surface. The outer root tissue may slough easily.
1402019	blue mold	Peronospora tabacina	Blue mold can occur in the plant bed or field. Circular yellow spots up to one inch in diameter develop on the leaves. Blue-gray fungal growth is produced on the underside of these spots when the fungus is active. Spots become light brown when the leaf tissue dies. The disease first develops on lower leaves, but it rapidly spreads to upper leaves during wet, cool weather.
1402056	bacterial barn rot		During curing or storage, leaves may be rotted or discolored by these bacteria. The symptoms first appear as blackening of the veins or midribs. Large areas or whole leaves may decay. This soft rot bacterium is present in the soil and on green leaves. Barn rot begins when leaves are harvested wet and not properly dried before curing. This bacterium also causes hollow stalk in the field under wet conditions.
1402017	genetic abnormalities		ruffles
1402015	herbicides (general)		Preplant incorporated herbicides may cause injury when improperly applied or not uniformly incorporated. Lateral roots may appear to be pruned, stubby, or stunted. Main roots may have areas without lateral roots. Irregular growth with stunting of the affected plants is above ground evidence of this injury. The pattern of occurrence in the field may relate to application or incorporation methods which resulted in accumulation of herbicide in "hot spots." Soil residues from excessive and/or multiple uses of dinitroanaline pesticides on sandy, low organic matter soils may retard early season growth of the next crops.
1402016	genetic abnormalities		Genetic abnormalities are not economically important but may be confused with infectious diseases or chemical injuries. The most common abnormalities are called chimeras, which are plants composed of two or more genetically different tissues caused by mutation in vegetative cells. They usually occur as pie-shaped sectors of leaves, stalks or flowers and appear on leaves as ruffled texture or irregular patches of yellow-green or white. Veins usually mark the boundaries of variegated leaf tissue.
1402036	tobacco cyst nematode	Globodera solanacearum	Plants infected by this nematode are stunted and have reduced root systems. Roots are pruned and may have brown decayed areas. Female nematodes, the size of tobacco seed, may be seen attached to the roots. They are round and vary in color from white to dark brown. Flowering of plants may be delayed up to two months, and leaves on infected plants are greener than normal. Stunted plants may appear to recover, but they will never achieve normal size. Root examination and soil assays are necessary for accurate diagnosis.
1440138	genetic abnormalities		Genetically abnormall tobacco plants, while usually of little or no economic importance, may be confused with infectious disease or chemical injuries. These abnormalities may be called monstosities, malformations, enations, anamolies, throwbacks, kickbacks, or runouts. It is unusual to find more than one of these abnormal plants in a field. Most fields contain none. Chimeras or variegated tobacco plants have irregular patches on the leaves that vary in color from creamy-white to yellow-green and give the plant a marbled or mottled appearance. Most variegated plants attain normal size, bloom normally, and produce seed. Sometimes abnormally shaped leaves appear on the affected plant. Patterns may be seen in the cured leaves from variegated plants. Another example of genetic abnormality is ruffles. Leaf margins roll downward, and leaves curve downward. Petioles may be elongated. The leaf blade margin may form pouches or folds upon itself, especially along veins on the underside of the leaf.
1402012	soil fumigant		Fumigant injury is indicated by a swollen main root which has almost no side roots, or a concentration of side roots near the soil surface. This problem may be caused by improper application or excessive rates of soil fumigants, wet soil conditions, or insufficient waiting time between fumigant application and transplanting.
1402009	cold injury (low temperature)		Temperatures near or below freezing may cause yellowing, stunting, and/or death of plants.
1402011	fertilization		Fertilizer, especially excessive quantities, placed too close to the roots can cause injury from the salts formed in solution. This type of injury is more likely to occur in sandy soils and during dry weather. Symptoms include: shriveled roots, very limited new root growth, and slow irregular above ground growth.
1402014	herbicides (general)		Preplant incorporated herbicides may cause injury when improperly applied or not uniformly incorporated. Lateral roots may appear to be pruned, stubby, or stunted. Main roots may have areas without lateral roots. Irregular growth with stunting of the affected plants is above ground evidence of this injury. The pattern of occurrence in the field may relate to application or incorporation methods which resulted in accumulation of herbicide in "hot spots." Soil residues from excessive and/or multiple uses of dinitroanaline pesticides on sandy, low organic matter soils may retard early season growth of the next crops.
1402013	soil fumigant		Fumigant injury is indicated by a swollen main root which has almost no side roots, or a concentration of side roots near the soil surface. This problem may be caused by improper application or excessive rates of soil fumigants, wet soil conditions, or insufficient waiting time between fumigant application and transplanting.
1402101	nutrient excess or toxicity (general)		Chlorine Toxicity (Cl); There is evidence that 20-30 lb/a of Cl may improve tobacco yield. Higher rates may reduce growth and cause leaves to become abnormally green, thickened, and brittle, with cupped leaf margins. Leaves may have a distinctive smooth, sleek appearance. Toxicity symptoms are more common when ammonium rather that nitrate nitrogen is used. Maintaining soil pH about 5.7-6.0 reduces Cl uptake. Cured leaves have dingy, uneven colors and may tend to absorb excess moisture.
1402097	magnesium deficiency		Magnesium (Mg) deficiency, sometimes called "sand drown," occurs primarily on sandy soils during seasons of excessive rainfall. The first symptom of deficiency is loss of green color from lower leaves. On individual leaves it begins at the tips and margins and proceeds toward the base and center. Interveinal tissues become chlorotic while veinal areas remain green (photo). In extreme cases, lower leaves turn almost white and chlorotic symptoms progress to higher leaves. Mg deficient leaves rarely develop necrotic spots. It may occur at any stage of growth but occurs most often following rapid growth during the leaf production phase (4-8 weeks after transplanting). High rates of K and/or Ca on low Mg soils may enhance Mg deficiency.
1402098	sulfur deficiency		Sulfur (S) deficiency is more likely on deep, coarse soils with low levels of organic matter when little or no fertilizer S has been applied. Since S may accumulate at lower soil depths, deficiencies normally occur during early growth before extensive root development. In contrast to N, the first symptom of S deficiency is a mild chlorosis of the upper leaves and bud. Unless the deficiency is alleviated, the entire plant will become chlorotic and flowering may be delayed. Another distinguishing difference between N and S deficiency is that the lower chlorotic leaves of S deficient plants are not lost by "firing" unless nitrogen is also deficient. Crops deficient is S show very little greening response to additional N until the S deficiency if corrected.
1402099	manganese deficiency		Manganese (Mn) deficiency occurs primarily on overlimed soils (pH above 6.2) which are also low in available Mn. A deficiency of Mn causes flecking on the lower leaves similar to that of weather fleck. In contrast to weather fleck, Mn deficient plants are stunted, and affected leaves are more chlorotic and eventually take on a "ragged" appearance as the flecks coalesce and dead tissue falls out. Subsequent growth usually appears normal, but flecking may advance to middle and occasionally to upper leaves if root development is restricted.
1402100	boron deficiency		Boron (B) deficiency is rare but is more likely to occur at soil pH above 6.2, especially on sandy soils following periods of high rainfall and/or rapid growth. Initially, the bud leaves become light green and distorted. In advanced stages, the terminal bud dies and the remaining leaves become abnormally thickened and tend to curl downward. Lower leaves become turgid and brittle as indicated by breaking of the midrib, which may cause leaf drop. The tissue of the broken midrib may be darkened.
1402092	nitrogen deficiency		Nitrogen (N) deficiency may result in retarded growth and leaves with a pale green color. Lower leaves yellow prematurely, are smaller, and tend to "fire" or dry up. The stalk is short and slender, leaves tend to be more upright than normal, and flowering is delayed. Premature flowering may result if certain stresses such as low temperatures or extremeness in soil moisture interfere with N uptake and use. Symptoms of deficiency usually appear first on the sandier areas of a field after excessive rain or irrigation even when adequate N fertilizer had been previously applied.
1402075	herbicides (general)		Triazines are a group of herbicides which include atrazine, cyanazine, propazine, ametryn, prometryn, simazine, and metribuzin. Substituted ureas are a group of herbicides which include linuron, diuron, fluometuron, and chloroxuron. Both triazines and ureas produce similar injury symptoms. Injury can be caused by foliar or root uptake. Mild symptoms from low levels first appear on the tips of older leaves as yellowing between the veins. As the injury increases, the areas between the veins turn brown and progress toward the base of the leaf. The leaves will die back from the tips and edges. Plants will be stunted but may survive from very low levels; however, plant death will occur from high levels. Foliar exposure can kill the plant; however, with low levels, yellow to white areas are formed, turn brown, and fall out. Ureas may produce a brighter yellow to white leaf mottling than triazines. Symptoms of injury from all herbicides in the triazine and urea groups are very similar and are difficult to separate.
1402069	lightning		Damage is usually in a circular pattern in the field. Plants nearest the strike will suddenly wilt and may die. Whole plants or individual leaves on plants in the surrounding area may also wilt. Some leaves will have black or shriveled midribs and veins. Areas of lamina may pucker because growth of the midribs or veins is reduced. The stalk may be hollow, or the pith may be disced with irregular separations. The pith remains white which differentiates lightning damage from black shank and hollow stalk.
1402095	potassium deficiency		Potassium (K) deficiency causes slight mottling and brownish-yellow spots on leaf tips. Later there are brownish-yellow spots on leaf tips. Later there are brownish-yellow spots along leaf margins that become necrotic and fall out, leaving a ragged appeareance. Leaves may be puckered, with the tips and margins curled downward. Symptoms first appear on lower leaves in young plants and upper leaves on older plants. Symptoms are more acute on rapidly growing plants and may be accentuated by excess N. Excess K does not causes visible symptoms.
1440064	drowning		Tobacco is very susceptible to water damage by flooding. Exposure to waterlogged soils for extended periods of time will cause the leaves to droop, turn yellow, and eventually die while the bud may remain green. Removal of the outer surface of the stalk will reveal discolored tissue. All degrees of injury may occur from complete root destruction to killing of only a few of the deeper roots. Apparent injury may be more severe on older plants than on young plants. Partial drowning may result in shallow root systems, stunted plants, and premature flowering.
1440003	canvas burn		Canvas Burn indicated by yellowing or damage on leaf margins or tips is sometimes considered as cold injury since it usually occurs as the bed cover rubs leaves when temperatures are near freezing.
1440002	cold injury (low temperature)		Plant stunting and cupping or strapping of expanding leaves may result from cold injury. The strapped leaves and the bud area usually turn whitish or sometimes yellowish in color and show a restricted portion in leaf width as growth progresses. Plants will suffer less cold injury if covers are applied on the ground with no openings left at the edges. Rips in covers should be mended promptly. No other treatment is suggested since affected plants will resume normal growth after four or five consecutive days of warm weather.
1402040	Phytophthora blight	Phytophthora nicotianae	Black shank infection may occur on lower leaves of a plant due to spores being splashed onto them by hard rains. Large lesions (up to 3 inches) with a greenish-brown to yellow color are formed on the infected leaves.
1440015	blue mold	Peronospora tabacina	Blue mold may occur on the plant anytime from seedling to harvest; however, young tissue is more susceptible than old tissue. The first evidence of blue mold in the field usually occurs on the leaves as yellow circular spots about the size of a nickel. The spots soon develop the characteristic bluish, downy fungal growth on the undersides of the leaves which is best seen in the morning when the leaf is wet. If spots develop on leaves that are expanding, a puckering of the leaf occurs. As spots age, they turn from yellow to tan or brown and often tear or drop out. If infection has occurred near or on a leaf vein, a localized systematic infection may occur. The affected vein becomes reddish-brown, and the area around the vein is yellowed and distorted. In newly set transplants, it is possible for the fungus to develop systematically, killing the main bud and resulting in stunting or death of the plant. Splitting the stalk of systematically infected plants reveals a reddish- brown discoloration in the vascular tissue beneath the epidermis. A one-sided systemically infection also occur, resulting in a deformed stalk and lodging of affected plants. During weather favorable for blue mold (cool, cloudy, and wet), the disease can develop rapidly, causing numerous leaf lesions which can result in leaf blighting and severe leaf loss. The disease may develop during hot, humid periods if cool nights exist.
1402121	tobacco flea beetle	Epitrix hirtipennis	Larvae live in the soil and feed on and burrow into the roots of tobacco plants.
1402134	spotted lady beetle	Coleomegilla maculata	Both adult and larval lady beetles are important predators of aphids. Adults can consume 50 aphids per day, while larvae kill 10 to 25 per day. The adult spotted lady beetle is bright red to pink with black spots on the wing covers and pronotum.
1402128	cabbage looper	Trichoplusia ni	Loopers are pale green, about one inch long when full grown, and taper slightly toward the head. There is a thin, white line along each side of the body and two others along the middle of the back. Larvae are characterized by the presence of three pairs of fleshy prolegs (in addition to three pairs of jointed legs behind the head) and their habit of moving in a "looping" motion. They generally feed on the undersides of leaves, leaving small to moderate size ragged holes. Larvae also spin silken cocoons on the undersides of leaves in which they pupate.
1402035	lesion nematode	Pratylenchus spp.	Root lesion nematode damage (also called brown root rot) usually occurs in well-defined areas in the field. Infected plants are stunted, yellowed, tend to wilt during the heat of the day, and "fire" along leaf margins. Root lesion nematodes enter the white feeder roots causing small, reddish-brown lesions. Severe infections cause extensive root pruning and root rot resulting in a tap root lacking lateral roots. Secondary root growth is abundant near the soil surface away from severe nematode activity. On some rotted roots, the tissue easily sloughs off in a sleeve-like fashion, leaving the stringy vascular cylinder.
1402003	blue mold	Peronospora tabacina	Blue mold is shown above in a plant bed, but it can also occur in the field.
1402119	tobacco flea beetle	Epitrix hirtipennis	Adult beetles are present on tobacco throughout the growing season (both in plant beds and in the field). Damage is characterized by small, round holes that give the leaves a "shot-hole" appearance. Injury is especially severe on newly transplanted tobacco. The lower leaves of larger plants can also be heavily damaged, especially near the base of the leaves. Adult beetles are brown with black markings and fine punctures on their wing covers. They are about 1/16 inch long. Adults pass the winter in grassy areas, woodlots, and other favorable sites in and around tobacco fields. The larvae are slender, white grubs 1/16 to 3/16 inch long with brown heads. Larvae live in the soil and feed on and burrow into the roots of tobacco plants. There are 3 to 5 generations of flea beetles per year. Several other species may occur in tobacco.
1402136	lady beetle		Larvae are elongate and taper towards the rear. They are about 1/3 inch long, velvety black with orange spots and are covered with black spines.
1402057	bacterial barn rot		During curing or storage, leaves may be rotted or discolored by these bacteria. The symptoms first appear as blackening of the veins or midribs. Large areas or whole leaves may decay. This soft rot bacterium is present in the soil and on green leaves. Barn rot begins when leaves are harvested wet and not properly dried before curing. This bacterium also causes hollow stalk in the field under wet conditions.
1402023	wildfire of tobacco	Pseudomonas syringae pv. tabaci	This bacterial disease can occur in the plant bed or field. It most commonly occurs in the field in mid-summer during periods of cloudy, wet weather. Leaf spots develop, which are 1/4 to 1/2 inch in diameter and dark brown to black in color. They are limited by leaf veins making spots angular in shape. Concentric rings may be evident within the spots. Spots may coalesce, forming large irregular dead areas. The center of the spots may fall out, giving the leaf a ragged appearance. Leaves will turn yellow when numerous spots are present. Angular leafspot is most severe on lower leaves.
1440100	tobacco wireworm	Conoderus vespertinus	Wireworms (various species) are the major soil insects attacking tobacco. The yellow to brown, hard-bodied larvae are slender and cylindrical. The adult is a click beetle. Wireworms hatch in the summer, spend the winter in the soil and are usually most destructive to newly transplanted tobacco. Wireworm larvae cut off small underground stems and roots and bore into larger stems and roots. They may be found tunneling in stems near the soil surface . Affected plants may become stunted or wilt and die within a few days. Tobacco following sod may be damaged by wireworms for one to five years because some species have long life cycles.
1440107	yellowstriped armyworm	Spodoptera ornithogalli	The yellowstriped armyworm, is an occasional pest of tobacco. Full-grown larvae are about one inch long. They are predominately glossy black to gray with several pairs of triangular spots on the upper side of the body. A prominent longitudinal yellow stripe runs along each side. A distinct black spot can be seen immediately behind the third pair of legs. Yellowstriped armyworms chew roughly rounded holes in tobacco leaves. Economic infestations are rare in tobacco fields. The insect may occasionally be found feeding in tobacco beds.
1440067	frenching		The young leaves of frenched plants are narrowed and drawn with chlorosis along the margins. The network of veins is a distinct dark green. As the leaf develops, only the midrib elongates, producing a thick straplike-leaf. Terminal growth ceases and a stunted plant with many small, narrow, distorted leaves results. Frenching is usually classified as a physiological disorder, but studies indicate that frenching can be caused by a toxin formed by Bacillus cereus, a bacterium commonly found in the soil. Frenching is often associated with soils of high pH and/or poor internal drainage. Proper soil drainage, a pH level below 6, and adequate fertilization will be beneficial in preventing frenching.
1440130	syrphid or flower flies		Syrphid larvae [Allograta obliqua (Say) and others] are greenish or brownish maggots that are predators of aphids. The larvae has an indistinct tapering head with mouth hooks on the anterior end. A pair of dorsal tracheal trunks, visible through the thin skin, make this maggot appear to have two longitudinal stripes along its back. Larvae feed on aphids by sucking out their body fluids. Depending on the species, a larva can consume 100-900 aphids during its lifetime. The brown pupal case is tear-dropped shaped with a prominent tube at the posterior end. The adult flies are brightly colored, wasp- like insects with bands across their abdomen. They are often seen hovering over plants. Syrphid flies have one pair of wings, while wasps have two pairs.
1440057	bacterial hollow stalk	Erwinia aroideae	Bacterial hollow stalk is first noticed when leaves begin to drop or turn yellow and hang down the stalk. A watery soft rot develops at the base of the affected leaves and often extends up the midrib. The disease may begin at any point of injury, but it often starts at injuries caused by topping or suckering. The pith in the center of the stalk is destroyed, leaving a hollow shell. As the disease moves down the stalk, the leaves droop. Later they drop off, leaving a bare stalk. Hollow stalk usually appears after topping or suckering and may continue to develop after the tobacco is hung in the barn, causing barn rot. Related bacteria may also cause a soft rot of lower leaves during rainy weather.
1440102	tobacco flea beetle	Epitrix hirtipennis	Tobacco flea beetles, are major pests of tobacco. The are brownish black beetles about 1/16-inch long. Feeding by adults gives leaves a characteristic shot-hole appearance. They attack plants in the seedbeds almost as soon as they come up, often ruining entire plant beds. After transplanting, beetles become continue chewing holes into the leaves until the crop is harvested, weakening the plants and decreasing the value of the leaves. Heavy feeding on newly-set plants may cause stunting, resulting in uneven stands. The white, larvae burrow into the soil and feed on the roots of tobacco, cutting off the small roots and sometimes tunneling into the stalk.
1440087	chemicals		Maleic hydrazide , applied after topping to prevent sucker growth, acts by inhibiting cell division. If it is applied to immature plants, the younger leaves become narrow and pale green, and stalk elongation is slowed or halted. Application of excessive rates may cause abnormal coloring and thickening of upper leaves as well as drooping of the tip leaves. The use of excessive pressure and/or improper nozzles may result in leaf scorch or burn, especially on hot days. Suckers existing on the plant at the time of application develop small, narrow leaves and are limited in growth. Application rate determines the response of the plant.
1440050	Phytophthora blight	Phytophthora nicotianae	Black shank is primarily a disease of the roots and the lower stalk of the tobacco. The symptoms of black shank vary with weather conditions, age of plants, stage of disease development, degree of plant resistance, and virulence of the soil-borne fungal pathogen. Stunting is often the first symptom of black shank, but the disease is seldom recognized until plants wilt. At first, wilted plants will recover in the evening hours, but later become permanently wilted, with leaves turning yellow and hanging down the stalk. During the early stages of disease development, an examination of the plant will show a black discoloration of one or more of the larger roots and the interior of the lower stalk. As the disease progresses, the lower part of the stalk becomes black near the soil line, hence the name black shank. In advanced stages of the disease, the tissues in the center of the lower stalk become blackened, and as the pith dries, it becomes segmented into discs.
1440095	slugs		Slugs, Limax spp., may be very damaging in plant beds, especially during cool, rainy springs. Slugs are shell-less snails. They have soft, legless, unsegmented bodies which vary from light yellow to gray- brown. The elongated body acts as a muscular foot that glides along on a mucous secretion which gives slugs their slimy appearance. Slugs feed at night, tearing ragged holes in the leaves with their rasplike mouthparts. Feeding damage and silvery slime trails may be the only clues to their presence because slugs hide under debris during the day.
1440049	Phytophthora blight	Phytophthora nicotianae	Black shank is primarily a disease of the roots and the lower stalk of the tobacco. The symptoms of black shank vary with weather conditions, age of plants, stage of disease development, degree of plant resistance, and virulence of the soil-borne fungal pathogen. Stunting is often the first symptom of black shank, but the disease is seldom recognized until plants wilt. At first, wilted plants will recover in the evening hours, but later become permanently wilted, with leaves turning yellow and hanging down the stalk. During the early stages of disease development, an examination of the plant will show a black discoloration of one or more of the larger roots and the interior of the lower stalk. As the disease progresses, the lower part of the stalk becomes black near the soil line, hence the name black shank. In advanced stages of the disease, the tissues in the center of the lower stalk become blackened, and as the pith dries, it becomes segmented into discs.
1440033	Tobacco Etch Virus	Potyvirus TEV	The first symptom of TEV infection is a pronounced vein clearing on expanding leaves. This is followed by necrosis of a thin line of tissue along the veins, resulting in an etched pattern. Subsequently, young leaves develop a mosaic which fades to mottling as the leaf ages. Etching and more pronounced veinal necrosis is common. Plant growth is retarded, resulting in stunting, especially when young plants are infected. The virus overwinters in perennial solanaceous weeds and is transmitted to tobacco by migrating aphids. TEV often occurs in combination with other aphid-borne viruses. Tobacco etch is one of the most common virus diseases of burley.
1440051	Phytophthora blight	Phytophthora nicotianae	Black shank is primarily a disease of the roots and the lower stalk of the tobacco. The symptoms of black shank vary with weather conditions, age of plants, stage of disease development, degree of plant resistance, and virulence of the soil-borne fungal pathogen. Stunting is often the first symptom of black shank, but the disease is seldom recognized until plants wilt. At first, wilted plants will recover in the evening hours, but later become permanently wilted, with leaves turning yellow and hanging down the stalk. During the early stages of disease development, an examination of the plant will show a black discoloration of one or more of the larger roots and the interior of the lower stalk. As the disease progresses, the lower part of the stalk becomes black near the soil line, hence the name black shank. In advanced stages of the disease, the tissues in the center of the lower stalk become blackened, and as the pith dries, it becomes segmented into discs.
1440128	lady beetle		Lady beetles [various species including convergent Hippodamia convergens Guerin-Meneville and spotted Coleomegills maculata fuscilabris (Musant)] are important predators of soft-bodied insects such as aphids. The adult stages are easily recognized by their convex bodies and distinctive coloration. The hard wing covers are often orange, yellow, or red with a pattern of dark spots. Adult convergent lady beetles are black with orange or red wing covers with 12 black spots (spots are sometimes indistinct). The pronotum has two converging lines and a white margin. The adult spotted lady beetle is bright red to pink with black spots on the wig covers and pronotum. Yellowish lady beetle eggs are laid in groups on plants infested with aphids. The lady beetle larvae is enlongated with a velvety black to blue body 1/3-inch long with orange spots and black spines. Adults can consume 50 aphids per day, while larvae kill 10 to 25 per day.
1440127	lady beetle		Lady beetles [various species including convergent Hippodamia convergens Guerin-Meneville and spotted Coleomegills maculata fuscilabris (Musant)] are important predators of soft-bodied insects such as aphids. The adult stages are easily recognized by their convex bodies and distinctive coloration. The hard wing covers are often orange, yellow, or red with a pattern of dark spots. Adult convergent lady beetles are black with orange or red wing covers with 12 black spots (spots are sometimes indistinct). The pronotum has two converging lines and a white margin. The adult spotted lady beetle is bright red to pink with black spots on the wig covers and pronotum. Yellowish lady beetle eggs are laid in groups on plants infested with aphids. The lady beetle larvae is enlongated with a velvety black to blue body 1/3- inch long with orange spots and black spines. Adults can consume 50 aphids per day, while larvae kill 10 to 25 per day.
1440104	tobacco flea beetle	Epitrix hirtipennis	Tobacco flea beetles, are major pests of tobacco. The are brownish black beetles about 1/16-inch long. Feeding by adults gives leaves a characteristic shot-hole appearance. They attack plants in the seedbeds almost as soon as they come up, often ruining entire plant beds. After transplanting, beetles become continue chewing holes into the leaves until the crop is harvested, weakening the plants and decreasing the value of the leaves. Heavy feeding on newly-set plants may cause stunting, resulting in uneven stands. The white, larvae burrow into the soil and feed on the roots of tobacco, cutting off the small roots and sometimes tunneling into the stalk.
1440108	Japanese beetle	Popillia japonica	Japanese beetles, occasionally feed on tobacco in groups, causing a skeletonization of the leaf. The beetles are less than 1/2- inch in length, shiny metallic green, with copper brown forewings. There are six tufts of white hairs on each side of the body near the outer margins of the wing covers. These adults usually emerge from the soil during late May. Their population peaks four to five weeks later. Feeding is the greatest on warm sunny days. A relative humidity below 60% retards flying and induces the insect to feed extensively. The larvae are white grubs that feed in the soil, devouring the roots of a large number of plants, especially turf grasses.
1440110	cabbage looper	Trichoplusia ni	The cabbage looper is a light green caterpillar with a thin white line along each side of the body. Two additional lines run along the midline of the back. Cabbage loopers have three pair of slender legs just behind the head and three pairs of fleshly legs near the rear end. The body tapers noticeably toward the head. An absence of legs in the mid-portion of the body results in the larvae moving with a "looping" motion. Cabbage loopers feed for two to four weeks, usually on the lower portion of the plant.
1440016	blue mold	Peronospora tabacina	Blue mold may occur on the plant anytime from seedling to harvest; however, young tissue is more susceptible than old tissue. The first evidence of blue mold in the field usually occurs on the leaves as yellow circular spots about the size of a nickel. The spots soon develop the characteristic bluish, downy fungal growth on the undersides of the leaves which is best seen in the morning when the leaf is wet. If spots develop on leaves that are expanding, a puckering of the leaf occurs. As spots age, they turn from yellow to tan or brown and often tear or drop out. If infection has occurred near or on a leaf vein, a localized systematic infection may occur. The affected vein becomes reddish-brown, and the area around the vein is yellowed and distorted. In newly set transplants, it is possible for the fungus to develop systematically, killing the main bud and resulting in stunting or death of the plant. Splitting the stalk of systematically infected plants reveals a reddish- brown discoloration in the vascular tissue beneath the epidermis. A one-sided systemically infection also occur, resulting in a deformed stalk and lodging of affected plants. During weather favorable for blue mold (cool, cloudy, and wet), the disease can develop rapidly, causing numerous leaf lesions which can result in leaf blighting and severe leaf loss. The disease may develop during hot, humid periods if cool nights exist.
1440058	bacterial hollow stalk	Erwinia aroideae	Bacterial hollow stalk is first noticed when leaves begin to drop or turn yellow and hang down the stalk. A watery soft rot develops at the base of the affected leaves and often extends up the midrib. The disease may begin at any point of injury, but it often starts at injuries caused by topping or suckering. The pith in the center of the stalk is destroyed, leaving a hollow shell. As the disease moves down the stalk, the leaves droop. Later they drop off, leaving a bare stalk. Hollow stalk usually appears after topping or suckering and may continue to develop after the tobacco is hung in the barn, causing barn rot. Related bacteria may also cause a soft rot of lower leaves during rainy weather.
1440048	root-knot nematode	Meloidogyne spp.	Plants affected by root-knot nematodes are characteristically stunted and yellow and appear in irregular patches within a field. Root knot is most easily identified by the knots or galls which develop on the roots of infected plants. These galls vary from pinhead size to many times thicker than the normal root. They are irregular in shape but are usually either spindle-shaped or spherical. Affected plants wilt rapidly during dry weather and may even wilt in the presence of adequate soil moisture. Plants infected with root knot often exhibit symptoms of drought or nutritional stress. Severely affected plants may die. Other soil-borne diseases such as Fusarium wilt or black shank are often more severe when root knot nematodes are present. In northern burley tobacco areas the disease is seldom found unless tobacco is planted in old garden site, sandy river bottoms, or following vegetables.
1440111	tobacco budworm	Heliothis virescens	The tobacco budworm is one of the most destructive pests of the tobacco. Eggs, laid by the adult moth on the tobacco leaves, hatch and eventually develop into 1 1/2-inch long larvae when full grown. The larvae are light to dark green and have several longitudinal pale stripes. They may chew small holes in the leaves before they reach the buds. Larvae then damage the bud or growing tip of the plant. They may appear any time during the growing season. The leaves that expand from the buds are often ragged and distorted. Because of their protected location on the plant, budworms are difficult to control. The corn earworm, Heliothis zea (Boddie), also attacks burley and is closely related to the budworm in appearance and feeding habits.
1440054	Phytophthora blight	Phytophthora nicotianae	Black shank is primarily a disease of the roots and the lower stalk of the tobacco. The symptoms of black shank vary with weather conditions, age of plants, stage of disease development, degree of plant resistance, and virulence of the soil-borne fungal pathogen. Stunting is often the first symptom of black shank, but the disease is seldom recognized until plants wilt. At first, wilted plants will recover in the evening hours, but later become permanently wilted, with leaves turning yellow and hanging down the stalk. During the early stages of disease development, an examination of the plant will show a black discoloration of one or more of the larger roots and the interior of the lower stalk. As the disease progresses, the lower part of the stalk becomes black near the soil line, hence the name black shank. In advanced stages of the disease, the tissues in the center of the lower stalk become blackened, and as the pith dries, it becomes segmented into discs.
1440031	Tobacco Ringspot Virus	Nepovirus TRSV	Tobacco ringspot has the most distinctive symptoms of the virus diseases. The name truly describes the disease because chlorotic or necrotic rings occur in the leaf. A concentric line pattern of chlorotic and necrotic tissue, often forming an "oak leaf" pattern, is very common. The symptoms occasionally are confirmed to one side of the plant. The disease appears early in the season, usually with initial growth after transplanting. Most infected plants recover as new symptomless leaves develop. The virus is transmitted by nematodes. In the field, infected plants may appear alone or clustered. Ringspot may occur in the plant bed.
1440023	wildfire of tobacco	Pseudomonas syringae pv. tabaci	Wildfire is caused by a strain of the same bacterium that causes angular leaf spot. The wildfire strain produces a toxin in which causes conspicuous chlorotic halos to develop around infection sites. Most burley varieties are resistant to wildfire.
1440024	brown spot	Alternaria alternata	Symptoms of the brown spot fungus first appear on the lower leaves. Spots are brown with sharply defined margins and may be surrounded by yellow halos. The primary distinguishing characteristics of brown spot are the dark concentric rings within spots that give it a target-like appearance. With magnification, reproductive structures of the casual agent are seen as tufts of black fungal spores (conidia). Under severe conditions, spots are numerous, may coalesce, and give the leaf a ragged appearance as the infected tissue falls out.
1440020	wildfire of tobacco	Pseudomonas syringae pv. tabaci	Symptoms of angular leaf spot in the field are similar to those produced in the plant bed. Spots are circular to slightly angular. After wet, rainy weather, spots may be numerous. The spots are tan at first but turn black with age. Centers of spots may drop out producing a shot-hole or ragged appearance. This bacterial disease is generally worse on the windward side of plants where watersoaking from driving rains or sandblasting tends to enhance infection.
1440021	wildfire of tobacco	Pseudomonas syringae pv. tabaci	Symptoms of angular leaf spot in the field are similar to those produced in the plant bed. Spots are circular to slightly angular. After wet, rainy weather, spots may be numerous. The spots are tan at first but turn black with age. Centers of spots may drop out producing a shot-hole or ragged appearance. This bacterial disease is generally worse on the windward side of plants where watersoaking from driving rains or sandblasting tends to enhance infection.
1440028	frog-eye leafspot	Cercospora nicotianae	Frogeye may develop on the leaves of tobacco in the plant bed, field, or barn. The spots on the leaves are quite distinct, typically circular, with a reddish-brown margin and tan or grey colored papery centers in which black masses (fruiting bodies) of the fungus may be found. Frogeye usually occurs on the lower leaves but moves up the plant as the season progresses, especially as the nitrogen supply is depleted. Sudden development of large dead in the upper leaves may occur near harvest. Frogeye may be confused with brown spot, wildfire, angular leaf spot, weather fleck, and physiological spotting, and it requires microscopic examination for diagnosis. Green spots on the leaves of cured tobacco may be the result of frogeye infection near harvest.
1440029	Tobacco Ringspot Virus	Nepovirus TRSV	Tobacco ringspot has the most distinctive symptoms of the virus diseases. The name truly describes the disease because chlorotic or necrotic rings occur in the leaf. A concentric line pattern of chlorotic and necrotic tissue, often forming an "oak leaf" pattern, is very common. The symptoms occasionally are confirmed to one side of the plant. The disease appears early in the season, usually with initial growth after transplanting. Most infected plants recover as new symptomless leaves develop. The virus is transmitted by nematodes. In the field, infected plants may appear alone or clustered. Ringspot may occur in the plant bed.
1402029	Potato Virus Y	Potyvirus PVY	Mild symptoms of this virus disease include leaf mottling and crinkling, prominent veins, and curved midribs. Leaf tissue, except for that around the veins, turns slightly yellow in color. This gives the veins a green-banded appearance. As the leaves mature, sunken brown spots may develop on the upper surface of the midrib. Systematic necrosis frequently occurs in cultivars resistant to root-knot nematodes. As lower leaves begin to ripen, midribs may turn black; leaves may die and fall from the stalk. If the stalk is split, areas of black discoloration will be found extending from top to bottom of the plant.
1402131	paper wasps	Polistes spp.	Several species of paper wasps search out and kill small hornworms and other tobacco pests. The wasps roll parts of the worms into balls, fly them to their nest, and feed them to their young. Research in the early 1960’s showed the provision of nesting sites near tobacco fields reduced numbers of hornworms and leaf loss. Most people recognize these beneficials as the familiar "stinging" wasps which build paper nests or combs under the eaves of buildings and in dense vegetation.
1402126	tobacco hornworm	Manduca sexta	Tobacco and tomato hornworms [Manduca sexta (Linnaeus), Manduca quinquemaculata (Hawthorn)]: These two species, usually referred to collectively as "hornworms," are potentially the most destructive insect pests of tobacco. Newly hatched larvae are ¼ inch long, pale green with a large horn at the posterior end. Larger larvae (up to 3 or 4 inches) are bright green in color. Tobacco hornworm larvae have seven white diagonal stripes on each side and a curved red horn. Tomato hornworms have eight white V-shaped marks on each side and the horn is straighter and blue-black. Small larvae chew small irregular holes in leaves. Larger larvae more often feed on leaf margins and may leave only the midribs of leaves.
1402123	tobacco budworm	Heliothis virescens	Tobacco budworm and corn earworm [Heliothis virescent (Fabricius), Helicoverpa zea (Boddie)]: Both species attack tobacco, but the budworm is predominant. Larvae of both species are closely related, similar in appearance, and cannot be distinguished with the naked eye. When fully developed, larvae can range from pale greenish-yellow to red-brown to nearly black. Most have pale striped running lengthwise on the body, and small dark spots may be visible on each body segment. All have five pairs of fleshly prolegs in addition to three pairs of jointed legs near the head. The primary distinguishing feature of these pests is their habit of feeding in the bud. As this damage expands with the leaf, large regular holes are produced. Both species may also top plants, tunnel into stalks or midribs of leaves, or feed on seed pods. After topping, they may produce more irregular holes in expanded leaves.
1402133	stilt bug	Jalysus wickhami	Stilt bugs are slender, brown bugs slightly over ½ inch in length when full grown. They have long, thread-like legs and antennae. Nymphs are similar to the adults but are smaller, lighter in color, and wingless. Stilt bugs are commonly seen walking slowly over tobacco plants or flying about the field in search of prey. These important beneficials feed on hornworm and budworm eggs (and to some extent on aphids) and may have a major impact on reducing damage caused by these pests.
1402103	vegetable weevil	Listroderes costirostris obliquus	Larvae are small legless grubs (1/4 - 3/8 inch long) and somewhat C-shaped. They are cream to green with dark heads and may be difficult to see against young leaves.
1402105	slugs		Slugs are not insects but are mullosks. They resemble snails in that they are legless, flattened soft-bodied creatures with few features other than a pair of antennae or feelers. Unlike snails, they lack shells. Young slugs may be small (1/2 inch long or less) and dull white. Older slugs are generally brown, gray or black. Some have darker spots. The largest species may be up to 7 inches long. Small slugs may simply rasp away the leaf surface. Larger slugs may eat small holes in leaves or eat large areas of leaves, especially along the margins. Silvery slime trails may be found, but the slugs usually hide beneath soil or debris during the day.
1402079	herbicides (general)		Injury symptoms from dicamba and picloram are identical but tobacco is much more sensitive to pircloram. Symptoms are somewhat similar to 2,4-D. Young leaves are often strapped, while the edges and tips of the leaves curl downward, giving a "parrot-beak" or "cobra-head" appearance. A small pointed tip usually protrudes from the end of the leaf. Leaf margins are not serrated as is common with 2,4-D. Severe injury is characterized by strapped and stubby young leaves. Bud leaves are often short and stubby with rounded tips.
1402114	Japanese beetle	Popillia japonica	Adult beetles are metallic green with copper-colored wings and tufts of white hair around the posterior end. They are 3/8 to ½ inch long. Adults appear during late spring and early summer and are most active on bright sunny days. They migrate into tobacco fields and often feed in groups on the upper leaves of scattered plants. Feeding holes are of moderate size and irregular or ragged, giving leaves a lacy appearance. Larvae are the grubs which feed in the soil on roots other than tobacco. They are about one inch long at maturity, white or grayish white with a reddish-brown head and are somewhat C-shaped.
1402115	Japanese beetle	Popillia japonica	They migrate into tobacco fields and often feed in groups on the upper leaves of scattered plants. Feeding holes are of moderate size and irregular or ragged, giving leaves a lacy appearance. Larvae are the grubs which feed in the soil on roots other than tobacco. They are about one inch long at maturity, white or grayish white with a reddish-brown head and are somewhat C-shaped.
1402109	whitefringed beetles	Naupactus spp.	The flightless adults are dark gray, short-snouted weevils with a line of white hairs along each side. Adults are active in midsummer and may leave sawtooth cuts along leaf margins but cause little real damage.
1402108	whitefringed beetles	Naupactus spp.	Larvae of this pest overwinter in the soil and feed under ground on roots and stems of recently set tobacco. This feeding may cause wilting, stunting or uneven stands. Yellow-white, legless grubs with light brown heads are heavy-bodied, slightly C-shaped, and up to ½ inch in length. They are often found in the soil near damaged plants or in stems.
1402081	herbicides (general)		Injury symptoms from dicamba and picloram are identical but tobacco is much more sensitive to pircloram. Symptoms are somewhat similar to 2,4-D. Young leaves are often strapped, while the edges and tips of the leaves curl downward, giving a "parrot-beak" or "cobra-head" appearance. A small pointed tip usually protrudes from the end of the leaf. Leaf margins are not serrated as is common with 2,4-D. Severe injury is characterized by strapped and stubby young leaves. Bud leaves are often short and stubby with rounded tips.
1402083	glyphosate		Glyphosate is a systemic herbicide that will produce injury in 5 to 7 days after exposure to the foliage. Injury frirst appears as a light yellow discoloration in the newly developing leaves. Leaf color changes from green to pale yellow and/or white from the base of the leaf to the tip. Newly formed leaves will be narrow, and the margins will be curled downwards. Symptoms on mature leaves will consist of areas of yellow or brown tissue between the veins while the remaining area of the leaf is normal. Dead areas will fall out, resulting in a "shot-hole" appearance. Areas around the veins will often be green with a yellow discoloration between the veins. Actively growing plants will die after exposure to glyphosate.
1402031	Tobacco Ringspot Virus	Nepovirus TRSV	The virus disease first appears as circular line patterns of yellow and brown tissue on young leaves. These line patterns may follow the leaf veins and form the outline of an oak leaf. Some of the plant tissue may die, resulting in a "shot-hole" appearance. Symptom severity varies from a few ringspots to a dwarfed plant with numerous patterns and ragged leaves. Ringspot usually appears on scattered plants and causes little or no economic loss.
1402026	Tobacco Mosaic Virus	Tobamovirus TMV	The first symptom of this virus disease is a light green coloration between the veins of young leaves. This is followed quickly by the development of a "mosaic" or mottled pattern of light and dark green areas in the leaves. These symptoms develop quickly and are more pronounced on younger leaves. Mosaic does not result in plant death, but if infection occurs early in the season, plants are stunted. Lower leaves are subject to "mosaic burn," especially during periods of hot and dry weather. In these cases, large dead areas develop in the leaves. This constitutes one of the most destructive phases of tobacco mosaic virus infection. Infected leaves may be crinkled, puckered, or elongated.
1402063	drought		Dry weather causes reduced leaf growth, along with wilting, yellowing, and subsequent "rimfire" or burning from the edges and between lateral veins of the lower leaves. Leaves tend to be more upright than normal, especially in the upper part of the stalk, giving the plant a "bunchy" appearance. Leaves become thicker than normal, and flowering is delayed. Leaves on older plants may develop whitish areas and take on a sunbaked appearance. Leaf maturity is delayed, and tobacco quality and yield may be greatly reduced. Symptoms may develop slowly as soil moisture is depleted. Plants on sandier portions of a field exhibit symptoms first.
1402039	Phytophthora blight	Phytophthora nicotianae	Plants cut longitudinally reveal brown to black discoloration of the pith, which is often separated into discs. Discing may not occur in resistant varieties and only a small portion of the pith may be discolored.
1402021	blue mold	Peronospora tabacina	Systemic infection begins in leaf veins which turn reddish. Systemically infected stalks are stunted. The leaves are mottled and distorted. When a leaf is removed, discolored vascular tissue is present where the leaf was attached. Often, this discoloration extends down the stalk. The terminal bud may die, and the central portion of the stalk in the terminal bud region will be darkened or deeply discolored. Excessive numbers of ground suckers may develop.
1402022	wildfire of tobacco	Pseudomonas syringae pv. tabaci	This bacterial disease can occur in the plant bed or field. It most commonly occurs in the field in mid-summer during periods of cloudy, wet weather. Leaf spots develop, which are 1/4 to 1/2 inch in diameter and dark brown to black in color. They are limited by leaf veins making spots angular in shape. Concentric rings may be evident within the spots. Spots may coalesce, forming large irregular dead areas. The center of the spots may fall out, giving the leaf a ragged appearance. Leaves will turn yellow when numerous spots are present. Angular leafspot is most severe on lower leaves.
1402025	brown spot	Alternaria alternata	This fungal disease appears first on the older leaves as circular, brown spots (1/4 to 1 1/4 inches in diameter) with sharply defined margins. Concentric circles (rings) are often noticeable within the spots. As the leaves approach maturity, a yellowish "halo" of varying width often forms around the lesion. Lesions may merge, forming large areas of dead tissue. During humid weather, sporulation of the fungus may be abundant, giving the lesions a black, dusty appearance. Brown spot is most severe as the plant approaches maturity, and the disease progresses from the lower to the upper leaves. Disease severity depends much on the weather, the overall health of the plant, varietal tolerance, and harvest rate.
1440077	herbicides (general)		Preplant incorporated herbicides, such as dinitroanalines, may cause injury to tobacco when they are improperly applied or not uniformly incorporated. Typical injury symptoms include seriously pruned root systems which result in stunted root growth and irregular field appearance. Affected plants exhibit a deficiency of feeder roots in the zone of herbicide incorporation. Most secondary and feeder roots terminate in blunt knob-like tips. Injury is also more common when cool wet weather persists after transplanting, or when excessively high rates of herbicides are used.
1402070	lightning		Damage is usually in a circular pattern in the field. Plants nearest the strike will suddenly wilt and may die. Whole plants or individual leaves on plants in the surrounding area may also wilt. Some leaves will have black or shriveled midribs and veins. Areas of lamina may pucker because growth of the midribs or veins is reduced. The stalk may be hollow, or the pith may be disced with irregular separations. The pith remains white which differentiates lightning damage from black shank and hollow stalk.
1440068	sunscald		Sunscald appears initially as a dark green, bruised portion of one or more leaves which later turns brown due to killing of leaf tissue. Wilted leaves exposed bright sunshine during hot weather and succulent tobacco that is undergoing a period of very rapid growth appear to be most susceptible. Shaded portions of wilted leaves that are not directly exposed to the sun tend to recover at night. Any type of injury that causes wilting, such as stink bug feeding, deep cultivation, or water damage, may contribute to sunscald.
1440092	calcium deficiency		Ca deficiency in burley tobacco is not common but sometimes occurs when soil exchange capacities and/or Ca saturation levels are low. Such conditions are most likely to occur in sandy soils with low pH. Ca deficiency symptoms first appear in the upper or youngest leaves because Ca is immobile within the plant. Typically, symptoms begin in the bud with the development of a pale green color, followed by rolling and downward curing of the new leaves. As the deficiency becomes more acute, dead or necrotic areas develop at tips and along edges of leaves. Under extreme deficiencies, the terminal bud eventually dies. Lower and middle leaves of Ca deficient plants may develop a darker a darker than normal green color.
1402020	blue mold	Peronospora tabacina	Systemic infection begins in leaf veins which turn reddish. Systemically infected stalks are stunted. The leaves are mottled and distorted. When a leaf is removed, discolored vascular tissue is present where the leaf was attached. Often, this discoloration extends down the stalk. The terminal bud may die, and the central portion of the stalk in the terminal bud region will be darkened or deeply discolored. Excessive numbers of ground suckers may develop.
1440022	wildfire of tobacco	Pseudomonas syringae pv. tabaci	Wildfire is caused by a strain of the same bacterium that causes angular leaf spot. The wildfire strain produces a toxin in which causes conspicuous chlorotic halos to develop around infection sites. Most burley varieties are resistant to wildfire.
1440131	Ichneumonid wasp	Campoletis sonorensis	The adult wasp is black, slender and about 1/4- inch long but is rarely recognized in the field. The female lays an egg beneath the skin of a small budworm. The egg hatches and larva develops inside the budworm. When development is complete, the parasitic larvae emerges and pupates outside attached to a tobacco leaf. The silken cocoon is white, oblong, and about 1/4 inch long and is frequently attached to the skin of the host budworm. This parasite may kill 70% to 80% of the budworms in a field.
1402120	tobacco flea beetle	Epitrix hirtipennis	Adult beetles are present on tobacco throughout the growing season (both in plant beds and in the field). Damage is characterized by small, round holes that give the leaves a "shot-hole" appearance. Injury is especially severe on newly transplanted tobacco. The lower leaves of larger plants can also be heavily damaged, especially near the base of the leaves. Adult beetles are brown with black markings and fine punctures on their wing covers. They are about 1/16 inch long. Adults pass the winter in grassy areas, woodlots, and other favorable sites in and around tobacco fields. The larvae are slender, white grubs 1/16 to 3/16 inch long with brown heads. Larvae live in the soil and feed on and burrow into the roots of tobacco plants. There are 3 to 5 generations of flea beetles per year. Several other species may occur in tobacco.
1440045	Rhizoctonia damping-off, blight and rot	Rhizoctonia solani	This fungus usually appears first in the plant bed, but infections occur at any growth stage. Sore shin appears as a brown discoloration of the transplant stem near or below the soil line. The affected area may increase in size after the plant is set in the field, sometimes extending several inches up the stalk. The stalk of an infected plant becomes brittle and may break up easily under pressure. Lower leaves of older plants may turn yellow; the plant is often stunted. Plants may wilt during the heat of the day. Diseased plants usually appear scattered in the field. In advanced stages of sore shin, large stalks may be dry and brown inside. Stalks with only slight infections produce near normal growth and yields unless the plants become stressed. Symptoms of sore shin may be confused with stem rot or black shank; accurate diagnosis requires microscopic examination.
1440098	vegetable weevil	Listroderes costirostris obliquus	The vegetable weevil, feeds as a larva and an adult, primarily at night. The adult is a dull gray-brown beetle, about 3/8- inch long, with a pale gray mark near the posterior end of each wing cover, forming an inconspicuous V-shaped spot. The pale green legless larvae have brown heads. Larvae may feed on tobacco in plant beds during early spring. Larvae may damage or destroy the bud and eat holes into the leaves. Larvae appear in spots and may damage a good size area. Because they feed mostly at night, it is difficult to locate them. However, the feeding damage is usually easy to see and should be used to determine the presence of this insect.
1440065	drowning		Tobacco is very susceptible to water damage by flooding. Exposure to waterlogged soils for extended periods of time will cause the leaves to droop, turn yellow, and eventually die while the bud may remain green. Removal of the outer surface of the stalk will reveal discolored tissue. All degrees of injury may occur from complete root destruction to killing of only a few of the deeper roots. Apparent injury may be more severe on older plants than on young plants. Partial drowning may result in shallow root systems, stunted plants, and premature flowering.
1440114	green peach aphid	Myzus persicae	The green peach aphid is a pale green, soft- bodied insect that is found in clusters on the underside of tobacco leaves. The 1/16-inch long "plant lice" use their sucking mouthparts to remove sap from the plants. Feeding by large numbers of aphids results in thin, lightweight leaves that may ripen prematurely. The sugar rich "honeydew" excreted by aphids builds up on the leaf surface and supports growth of black, sooty mold. The honeydew may cause leaves to stick together and cure to a dark, off-color of poor quality. Green peach aphids may transmit viruses such as tobacco vein mottling virus through their mouthparts. Aphid populations build up after winged females fly into tobacco fields, usually during the middle portion of the growing season. They settle on the leaf to feed and give birth to living young. Large populations can build up in a short period of time due to their short life cycle and the occurrence of several generations during a growing season.
1402018	blue mold	Peronospora tabacina	Blue mold can occur in the plant bed or field. Circular yellow spots up to one inch in diameter develop on the leaves. Blue-gray fungal growth is produced on the underside of these spots when the fungus is active. Spots become light brown when the leaf tissue dies. The disease first develops on lower leaves, but it rapidly spreads to upper leaves during wet, cool weather.
1440116	green peach aphid	Myzus persicae	The green peach aphid is a pale green, soft- bodied insect that is found in clusters on the underside of tobacco leaves. The 1/16-inch long "plant lice" use their sucking mouthparts to remove sap from the plants. Feeding by large numbers of aphids results in thin, lightweight leaves that may ripen prematurely. The sugar rich "honeydew" excreted by aphids builds up on the leaf surface and supports growth of black, sooty mold. The honeydew may cause leaves to stick together and cure to a dark, off-color of poor quality. Green peach aphids may transmit viruses such as tobacco vein mottling virus through their mouthparts. Aphid populations build up after winged females fly into tobacco fields, usually during the middle portion of the growing season. They settle on the leaf to feed and give birth to living young. Large populations can build up in a short period of time due to their short life cycle and the occurrence of several generations during a growing season.
1402124	tobacco budworm	Heliothis virescens	Tobacco budworm and corn earworm [Heliothis virescent (Fabricius), Helicoverpa zea (Boddie)]: Both species attack tobacco, but the budworm is predominant. Larvae of both species are closely related, similar in appearance, and cannot be distinguished with the naked eye. When fully developed, larvae can range from pale greenish-yellow to red-brown to nearly black. Most have pale striped running lengthwise on the body, and small dark spots may be visible on each body segment. All have five pairs of fleshly prolegs in addition to three pairs of jointed legs near the head. The primary distinguishing feature of these pests is their habit of feeding in the bud. As this damage expands with the leaf, large regular holes are produced. Both species may also top plants, tunnel into stalks or midribs of leaves, or feed on seed pods. After topping, they may produce more irregular holes in expanded leaves.
1440044	Rhizoctonia damping-off, blight and rot	Rhizoctonia solani	This fungus usually appears first in the plant bed, but infections occur at any growth stage. Sore shin appears as a brown discoloration of the transplant stem near or below the soil line. The affected area may increase in size after the plant is set in the field, sometimes extending several inches up the stalk. The stalk of an infected plant becomes brittle and may break up easily under pressure. Lower leaves of older plants may turn yellow; the plant is often stunted. Plants may wilt during the heat of the day. Diseased plants usually appear scattered in the field. In advanced stages of sore shin, large stalks may be dry and brown inside. Stalks with only slight infections produce near normal growth and yields unless the plants become stressed. Symptoms of sore shin may be confused with stem rot or black shank; accurate diagnosis requires microscopic examination.
1402064	sunscald		Sunscald is the result of the root system being unable to absorb adequate quantities of water to maintain turgidity in the entire plant. Rapid wilting and death of portions of recently expanded leaves may occur in the plant bed or field during periods of bright sunshine, high temperatures, and low humidity. Sunscald occurs most often after periods of rapid growth and affects the tender succulent leaves exposed to the sun. The affected area turns brown, and shattering of the dead tissue eventually follows. Rapid decline in soil moisture, root pruning by cultivation, poor drainage, or other root disturbances contribute to the severity of sunscald. Stink bugs cause similar symptoms but usually less damage.
1440103	tobacco flea beetle	Epitrix hirtipennis	Tobacco flea beetles, are major pests of tobacco. The are brownish black beetles about 1/16-inch long. Feeding by adults gives leaves a characteristic shot-hole appearance. They attack plants in the seedbeds almost as soon as they come up, often ruining entire plant beds. After transplanting, beetles become continue chewing holes into the leaves until the crop is harvested, weakening the plants and decreasing the value of the leaves. Heavy feeding on newly-set plants may cause stunting, resulting in uneven stands. The white, larvae burrow into the soil and feed on the roots of tobacco, cutting off the small roots and sometimes tunneling into the stalk.
1440091	potassium deficiency		Symptoms of K deficiency in tobacco first appear on lower or middle leaves and move up the plant as the problem becomes more severe. The distinguishing characteristic is mottled or "scorched" appearance that develops at the tips and along the edges of leaves. In the early stages, mottles are pale green or yellow, followed by the development of brown or dead centers. As the deficiency increases, mottles tend to run together and the dead areas fall out resulting in ragged leaf margins. Because the remaining green areas continue to grow, leaves often develop a crumpled or puckered appearance with edges cupping downward. K deficiencies appear to be encouraged by dry weather. Also, tobacco is usually less stunted by a deficiency of K than by a deficiency of either N or P.
1440126	grasshoppers		Grasshoppers [various species including differential grasshopper, Melanoplus differntialis (Thomas) and redlegged grasshopper, Melanoplus femurrubrum (DeGeer)] chew irregular holes between veins of leaves. Adult redlegged grasshoppers are 3/4 to 1 inch long. They are greenish-gray to olive-green or reddish-brown with a yellowish underside. The hind tibiaae are red with black spines. The differential grasshopper is 1 1/2 to 2-inches long with a shiny, brownish-yellow color and black V-shaped marks on the outer face of the yellow femur. Immature (nymphs) are similar but lack fully developed wings. Most species prefer other plants but will eat tobacco if their food supply is inadequate. Grasshoppers often migrate into tobacco fields from ditch banks and grasslands, especially when populations are high during droughts and following hay mowing or other habitiat modifications. Tobacco injury usually starts along the edges of fields and is more common late in the growing season.
1402125	tobacco budworm	Heliothis virescens	Tobacco budworm and corn earworm [Heliothis virescent (Fabricius), Helicoverpa zea (Boddie)]: Both species attack tobacco, but the budworm is predominant. Larvae of both species are closely related, similar in appearance, and cannot be distinguished with the naked eye. When fully developed, larvae can range from pale greenish-yellow to red-brown to nearly black. Most have pale striped running lengthwise on the body, and small dark spots may be visible on each body segment. All have five pairs of fleshly prolegs in addition to three pairs of jointed legs near the head. The primary distinguishing feature of these pests is their habit of feeding in the bud. As this damage expands with the leaf, large regular holes are produced. Both species may also top plants, tunnel into stalks or midribs of leaves, or feed on seed pods. After topping, they may produce more irregular holes in expanded leaves.
1440096	green June beetle	Cotinis nitida	The green June beetle larva, (Cotinis nitada (Linnaeus), can be a serious pest of tobacco plant beds. Eggs are laid during the summer. Larvae hatch and grow to be about two inches in length. They have brown head and creamy white C-shaped bodies. June beetles overwinter in the larval stage, complete their development the following spring, and are nearly full grown when beds are started. Larvae live several inches below the soil surface and cause some damage by feeding on young tender roots of plants. They cause the most serious damage by their continual burrowing and tunneling through the soil, loosening the soil and uprooting plants.
1402041	Southern bacterial wilt	Ralstonia solanacearum (except Race 3 Biovar 2)	The first symptom of this bacterial disease is the drooping of one or two leaves which may recover at night. Only half of a leaf may wilt initially. Leaves on one sides of the plant wilt first, while leaves on the other side appear normal. This unilateral wilting is very characteristic. Affected leaves become light green to yellow and occasionally appear scaled. Eventually most or all of the roots become blackened and decay. Infected roots become soft and slimy if adequate water is present. Tan or brown discoloration develops in the vascular tissue just beneath the bark. Pith and cortex also become discolored when involved. Longitudinal sections through affected stalks have narrow, brown lines in the xylem tissue nearest the pith. A slimy substance often oozes from a stalk cut in cross section. If a stalk segment containing discolored vascular tissue is placed in a clear container of water, milky strands stream from the edge of the tissue.
1440039	Tobacco Streak Virus	Ilarvirus TSV	Streak in burley tobacco follows a typical pattern wherein vigorously growing plants suddenly develop a severe necrotic streaking of the bud leaves and stalk. The stalk is marked by a depressed dark area, and the midveins of the leaves have dead streaks in them. The leaves curl downward, are distorted, wilted, and usually chlorotic. When death of the affected plant seems imminent, growth resumes from the bud with resulting leaves appearing normal except for occasional faint mottling. Leaves damaged early are permanently dwarfed and exhibit numerous necrotic areas. The virus is common in sweet clover and is presumably moved to tobacco by an insect, probably by thrips.
1440112	tobacco budworm	Heliothis virescens	The tobacco budworm is one of the most destructive pests of the tobacco. Eggs, laid by the adult moth on the tobacco leaves, hatch and eventually develop into 1 1/2-inch long larvae when full grown. The larvae are light to dark green and have several longitudinal pale stripes. They may chew small holes in the leaves before they reach the buds. Larvae then damage the bud or growing tip of the plant. They may appear any time during the growing season. The leaves that expand from the buds are often ragged and distorted. Because of their protected location on the plant, budworms are difficult to control. The corn earworm, Heliothis zea (Boddie), also attacks burley and is closely related to the budworm in appearance and feeding habits.
1440132	Tachinid flies		Tachinid flies including Zygostrumia and Winthemia species, belong to a large family of parasitic flies. These flies are hairy and resemble house flies, but some species are slightly larger. The tip of the abdomen may be red. Most lay large eggs on the body of budworms and hornworms. Caterpillars may be found with several tachinid larvae on them. Upon hatching, the tachinid larva usually burrows into the host and feeds internally. The parasitized insect usually dies while in the soil during the pupal stage, before it can transform into an adult and initiate a new generation.
1440106	variegated cutworm	Peridroma saucia	The variegated cutworm, may be a serious problem during the mid- portion of the growing season. This climbing cutworm usually feeds in the buds and on the leaves of tobacco plants. Larvae vary widely in color. The posterior segment is enlarged and blunt. A row of whitish or yellowish dots is visible down the middle of the back. The full grown larva usually has a mark on the back of the eighth abdominal segment, followed by a conspicuous yellow or orange area. There is usually a narrow orange-brown stripe on the sides. The variegated cutworm passes the winter in the pupal stage.
1402104	vegetable weevil	Listroderes costirostris obliquus	Adult weevils are grayish-brown snout beetles about 1/4 inch long and usually have a light V-shaped making near the apex of the wing covers.
1440055	Fusarium wilt	Fusarium oxysporum f.sp. nicotianae	Fusarium wilt usually appears in clusters of plants in the field. Yellowing and drying of the leaves on one side of a tobacco plant are typical symptoms. If a strip of the outer stem tissue (bark) is removed from the side of the stalk with yellowed leaves, a brown discoloration of the wood or vascular tissue is present rather than the normal white color. This discoloration usually can be traced from the affected part of the stalk down into the roots. The midribs of leaves on the affected side of the plant are often curved to one side with half of the leaf yellowed and the other half remaining green. In a young plant, the bud may bend toward the side of the plant with the yellowed leaves. Wilting, although implied by the name of this fungal disease, is not typical of diseased plants.
1440078	herbicides (general)		Phenoxy herbicides such as 2,4-D, dicamba, and MCPA on tobacco cause symptoms which vary with the herbicide rate and the age of the affected plants. Young leaves become stiff, puckered, elongated, and often have serrated edges. Midribs of affected leaves are prominent and may extend as a pointed needle-like projection or tail at the end of the leaf. Higher dosages cause the leaves to be "strappy" in appearance. High rates may also cause extensive twisting of stalks and leaf petioles. On older plants, leaf margins will curl downward, and the midrib will bend downward.
1402062	weather fleck		Soon after exposure to high levels of atmospheric pollutants, leaves may develop dark green water-soaked spots about 1/10 inch in diameter. Within hours, the spots turn dark brown, sometimes remain brown, but often turn white within 48 hours. Symptoms occur most often in low areas of fields. Plants are most sensitive when growing rapidly (plant bed and 4-6 weeks after transplanting), but symptoms may appear at any stage of growth. In the plant bed or on very sensitive varieties, spots appear over the entire leaf surface but are usually confined to the leaf tips of less sensitive varieties. Occasionally spots coalesce, or a central spot may be surrounded by smaller ones. Weather fleck is often confused with other flecks caused by chemicals, diseases, or nutritional disorders.
1440001	cold injury (low temperature)		Plant stunting and cupping or strapping of expanding leaves may result from cold injury. The strapped leaves and the bud area usually turn whitish or sometimes yellowish in color and show a restricted portion in leaf width as growth progresses. Plants will suffer less cold injury if covers are applied on the ground with no openings left at the edges. Rips in covers should be mended promptly. No other treatment is suggested since affected plants will resume normal growth after four or five consecutive days of warm weather.
1402116	tobacco aphid	Myzus nicotianae	Several species of aphids or plant lice feed on tobacco, but only the tobacco aphid commonly builds up large colonies. Winged aphids fly to plants in the bed or field and being producing wingless young (nymphs). Wingless, aphids are softbodied, pink to red, pale green to yellow-green, pear-shaped, and only about 1/16 inch long when full grown. Most aphids are wingless even as adults, but darker, winged forms may also be produced. Aphids have beak-like mouthparts through which they suck plant juices. In addition, they produce a sticky waste product, honeydew, on which sooty mold develop. As a result of these factors, both yield and quality may be reduced. (This and other species of aphids may also transmit certain virus diseases.) Infestations are characterized by the presence of aphids (mostly on the underside of upper leaves), shiny or greasy honeydew deposits on the upper surface of leaves, and sooty mold. In recent years, the red (pink) form of the tobacco aphid has become much more prevalent than the green form.
1440113	tobacco budworm	Heliothis virescens	The tobacco budworm is one of the most destructive pests of the tobacco. Eggs, laid by the adult moth on the tobacco leaves, hatch and eventually develop into 1 1/2-inch long larvae when full grown. The larvae are light to dark green and have several longitudinal pale stripes. They may chew small holes in the leaves before they reach the buds. Larvae then damage the bud or growing tip of the plant. They may appear any time during the growing season. The leaves that expand from the buds are often ragged and distorted. Because of their protected location on the plant, budworms are difficult to control. The corn earworm, Heliothis zea (Boddie), also attacks burley and is closely related to the budworm in appearance and feeding habits.
1402055	bacterial soft rot	Pectobacterium carotovorum ssp. carotovorum	This bacterial soft rot usually first appears following topping and suckering. Although the bacteria can invade the stalk through any wound, they usually enter through the break at the top. The pith rapidly turns brown and collapses in a watery rot. A foul odor is evident as the stalks become hollow. Leaves adjacent to the rotting pith will wilt. The rot may extend into the leaves through the midrib. The midribs turn black and the leaves droop. If infected leaves are placed in the barn, soft rot may continue to develop as barn rot.
1402110	cutworms, loopers, owlet moths, and underwings		Cutworms [various species including black cutworm, Agrotis ipsilon (Hufnagel); granulate, Feltia subterranean (Fabricius); and variegated Peridroma saucia (Hubner)]: In plant beds, cutworms may feed on stems at the soil surface, cut off buds, or eat holes in leaves. In recently transplanted fields, plants may be cut off just above ground level and individual leaves or buds may be cut off. A few species eat holes in the leaves. If cutworms are suspected as a cause of damage, dig around damaged plants (cutworms usually hide beneath soil, detached leaves or debris during the day). Cutworms are generally soft-bodied, dirty gray to brown to black, variously marked with dark spots or lines and usually 1-2 inches long. They curl up when disturbed.
1402102	vegetable weevil	Listroderes costirostris obliquus	Larvae and sometimes adults may feed on buds and leaves in plant beds. Adults may occasionally attack newly transplanted tobacco, feeding on leaves and stems. Feeding holes are ragged and may resemble grasshopper damage, but vegetable weevils nearly always cause some stem damage.
1402130	grasshoppers		Grasshoppers [various species including the differential grasshopper, Melanoplus differentialis (Thomas) and southern red-legged grasshopper are ¾ to 1 inch long. They are greenish-gray to olive-green or reddish-brown with a yellowish underside. The hind tibiae are red with black spines. The differential grasshopper is 1½ to 2-inches long with a shiny, brownish-yellow color and black V-shaped marks on the outer face of the yellow femur. Immatures (nymphs) are similar but lack fully developed wings. Grasshoppers damage tobacco by chewing ragged holes in the leaves. Most species prefer other plants but will eat tobacco if their food supply is inadequate. Grasshoppers often migrate into tobacco fields from hay fields, pastures, and old fields, especially when populations are high during droughts and following hay mowing or other habitat modifications.
1402122	tobacco flea beetle	Epitrix hirtipennis	The lower leaves of larger plants can also be heavily damaged, especially near the base of the leaves.
1402008	anthracnose	Colletotrichum nicotianae	This fungal disease is encountered in tobacco seed beds and occasionally in the field. Small gray-white, usually circular, spots develop on leaves. As lesions age and dry, they become papery and thin and are surrounded by a raised water-soaked border. Leaf tissues, especially veins and midribs, may appear "pitted" or sunken when viewed from the underside. The lesions become brown. Larger spots may have a dark brown center. Lateral veins on the lower leaf surface may turn dark. Affected leaves may become wrinkled and/or distorted. As the disease continues, the entire leaf may die. Small plants may be killed, resulting in large barren spots in plant beds. In the field, leaf lesions may be followed by cankers on midribs and stems. Anthracnose is favored by wet conditions and is sometimes confused with weather fleck. Symptoms of anthracnose are also similar to those of target spot. Target spot has more consistently circular, pin-head sized lesions which usually do not affect the major leaf veins until the whole leaf begins to die, whereas anthracnose often attacks leaf veins and petioles early in the disease development.
1402010	tobacco wireworm	Conoderus vespertinus	Wireworm damage may first appear as stunted or irregular plant growth. Holes and tunneling in plant stems just below the soil line and scars on root surfaces often indicate wireworm or other insect feeding.
1402027	Tobacco Mosaic Virus	Tobamovirus TMV	The first symptom of this virus disease is a light green coloration between the veins of young leaves. This is followed quickly by the development of a "mosaic" or mottled pattern of light and dark green areas in the leaves. These symptoms develop quickly and are more pronounced on younger leaves. Mosaic does not result in plant death, but if infection occurs early in the season, plants are stunted. Lower leaves are subject to "mosaic burn," especially during periods of hot and dry weather. In these cases, large dead areas develop in the leaves. This constitutes one of the most destructive phases of tobacco mosaic virus infection. Infected leaves may be crinkled, puckered, or elongated.
1440046	black root rot	Thielaviopsis basicola	Uneven growth of tobacco in the field is indicative of black root rot. Affected plants often become yellowed and are smaller than neighboring healthy plants. Stunting is more evident during the early part of the growing season and during cool, wet seasons. On hot days, leaves of the diseased plants wilt more rapidly than those of healthy plants, but recover during the night. Plants usually grow out of the problem as soil temperatures rise, unless the variety is highly susceptible to the fungus and cool, wet soil conditions prevail. the most distinctive symptoms of black root rot occur on the roots. The entire root system is greatly reduced with smaller roots exhibiting a typical brown to black discoloration of their tips, and larger roots having brown or black spots on their surface. The outer root tissue may slough easily.
1440109	Japanese beetle	Popillia japonica	Japanese beetles, occasionally feed on tobacco in groups, causing a skeletonization of the leaf. The beetles are less than 1/2-inch in length, shiny metallic green, with copper brown forewings. There are six tufts of white hairs on each side of the body near the outer margins of the wing covers. These adults usually emerge from the soil during late May. Their population peaks four to five weeks later. Feeding is the greatest on warm sunny days. A relative humidity below 60% retards flying and induces the insect to feed extensively. The larvae are white grubs that feed in the soil, devouring the roots of a large number of plants, especially turf grasses.
1440129	lady beetle		Lady beetles [various species including convergent Hippodamia convergens Guerin-Meneville and spotted Coleomegills maculata fuscilabris (Musant)] are important predators of soft-bodied insects such as aphids. The adult stages are easily recognized by their convex bodies and distinctive coloration. The hard wing covers are often orange, yellow, or red with a pattern of dark spots. Adult convergent lady beetles are black with orange or red wing covers with 12 black spots (spots are sometimes indistinct). The pronotum has two converging lines and a white margin. The adult spotted lady beetle is bright red to pink with black spots on the wig covers and pronotum. Yellowish lady beetle eggs are laid in groups on plants infested with aphids. The lady beetle larvae is enlongated with a velvety black to blue body 1/3- inch long with orange spots and black spines. Adults can consume 50 aphids per day, while larvae kill 10 to 25 per day.
1402139	red-tailed wasp	Cardiochiles nigriceps	These small wasps are parasites of budworms. They are about 3/8 inch long. Although the wings and front portion of these wasps are black and only the abdomen and hind legs are red, they appear red in color. Red-tail wasps are often seen hovering over tobacco buds or flowers in search of small budworm larvae. Once a female finds a larva, she inserts an egg into its body. The parasitized budworm will look normal and continue to develop to the 4th or 5th stage before it prematurely pupates and dies.
1440137	genetic abnormalities		Genetically abnormall tobacco plants, while usually of little or no economic importance, may be confused with infectious disease or chemical injuries. These abnormalities may be called monstosities, malformations, enations, anamolies, throwbacks, kickbacks, or runouts. It is unusual to find more than one of these abnormal plants in a field. Most fields contain none. Chimeras or variegated tobacco plants have irregular patches on the leaves that vary in color from creamy-white to yellow-green and give the plant a marbled or mottled appearance. Most variegated plants attain normal size, bloom normally, and produce seed. Sometimes abnormally shaped leaves appear on the affected plant. Patterns may be seen in the cured leaves from variegated plants. Another example of genetic abnormality is ruffles. Leaf margins roll downward, and leaves curve downward. Petioles may be elongated. The leaf blade margin may form pouches or folds upon itself, especially along veins on the underside of the leaf.
1440097	vegetable weevil	Listroderes costirostris obliquus	The vegetable weevil, feeds as a larva and an adult, primarily at night. The adult is a dull gray-brown beetle, about 3/8- inch long, with a pale gray mark near the posterior end of each wing cover, forming an inconspicuous V-shaped spot. The pale green legless larvae have brown heads. Larvae may feed on tobacco in plant beds during early spring. Larvae may damage or destroy the bud and eat holes into the leaves. Larvae appear in spots and may damage a good size area. Because they feed mostly at night, it is difficult to locate them. However, the feeding damage is usually easy to see and should be used to determine the presence of this insect.
1440066	frenching		The young leaves of frenched plants are narrowed and drawn with chlorosis along the margins. The network of veins is a distinct dark green. As the leaf develops, only the midrib elongates, producing a thick straplike-leaf. Terminal growth ceases and a stunted plant with many small, narrow, distorted leaves results. Frenching is usually classified as a physiological disorder, but studies indicate that frenching can be caused by a toxin formed by Bacillus cereus, a bacterium commonly found in the soil. Frenching is often associated with soils of high pH and/or poor internal drainage. Proper soil drainage, a pH level below 6, and adequate fertilization will be beneficial in preventing frenching.
1402094	phosphorous deficiency		Delayed growth, particularly in the early season, is typical of Phosphorus (P) deficiency. Plants may be dark green in color if N levels are adequate, and leaves may be narrower than normal. Small, necrotic spots may appear on the lower leaves when deficiency is severe. Due to generally adequate levels of P in previously cropped and well-fertilized soils, deficiencies of this element are rare and often temporary. Photo shows plants in a low P soil on right. P shortages may be induced if root growth is restricted. High soil or fertilized if root growth is restricted. High soil or fertilizer P levels may result in more rapid early growth but not increased yields. As the root system expands, growth differences between various P levels become less apparent.
1402141	Ichneumonid wasp	Campoletis sonorensis	The adult wasp is black, slender and about ¼ inch long but is rarely recognized in the field. The female lays an egg beneath the skin of a small budworm. The egg hatches and the larva develops inside the budworm. When development is complete, the parasitic larva emerges and pupates outside attached to a tobacco leaf. The cocoon is white, oblong, about ¼ inch long and is frequently attached to the skin of the host budworm.
1440079	herbicides (general)		Phenoxy herbicides such as 2,4-D, dicamba, and MCPA on tobacco cause symptoms which vary with the herbicide rate and the age of the affected plants. Young leaves become stiff, puckered, elongated, and often have serrated edges. Midribs of affected leaves are prominent and may extend as a pointed needle-like projection or tail at the end of the leaf. Higher dosages cause the leaves to be "strappy" in appearance. High rates may also cause extensive twisting of stalks and leaf petioles. On older plants, leaf margins will curl downward, and the midrib will bend downward.
1440052	Phytophthora blight	Phytophthora nicotianae	Black shank is primarily a disease of the roots and the lower stalk of the tobacco. The symptoms of black shank vary with weather conditions, age of plants, stage of disease development, degree of plant resistance, and virulence of the soil-borne fungal pathogen. Stunting is often the first symptom of black shank, but the disease is seldom recognized until plants wilt. At first, wilted plants will recover in the evening hours, but later become permanently wilted, with leaves turning yellow and hanging down the stalk. During the early stages of disease development, an examination of the plant will show a black discoloration of one or more of the larger roots and the interior of the lower stalk. As the disease progresses, the lower part of the stalk becomes black near the soil line, hence the name black shank. In advanced stages of the disease, the tissues in the center of the lower stalk become blackened, and as the pith dries, it becomes segmented into discs.
1402140	red-tailed wasp	Cardiochiles nigriceps	These small wasps are parasites of budworms. They are about 3/8 inch long. Although the wings and front portion of these wasps are black and only the abdomen and hind legs are red, they appear red in color. Red-tail wasps are often seen hovering over tobacco buds or flowers in search of small budworm larvae. Once a female finds a larva, she inserts an egg into its body. The parasitized budworm will look normal and continue to develop to the 4th or 5th stage before it prematurely pupates and dies.
1402118	tobacco aphid	Myzus nicotianae	Aphids have beak-like mouthparts through which they suck plant juices. In addition, they produce a sticky waste product, honeydew, on which sooty mold develop.
1440075	herbicides (general)		Triazines are a group of herbicides which include atrazine, cyanazine, propazine, ametryn, prometryn, simazine, and metribuzin. Substituted ureas are a group of herbicides which include linuron, diuron, flometruron, and chloroxuron. Both triazines and urea produce similar symptoms. Injury may be caused foliar or root absorption. Low levels produce mild symptoms which first appear on the tips of the older leaves as a yellowing between the veins. As the degree of injury increases, the areas between the veins turn brown and progress toward the base of the leaf. The leaf will die back from the tips and the edges. Plants will be stunted, but may survive very low level exposure, however, plant death occurs from high level exposure. Foliar exposure can kill the plant, but at low levels, yellow to white areas are formed on the leaf which will turn brown and fall out. Ureas may produce a brighter yellow to white leaf mottling than the triazines. Symptoms of injury from herbicides in the triazine and ureas groups are similar and are difficult to separate.
1440011	nitrogen deficiency		Nitrogen (N) deficiency; The two most common symptoms of N deficiency in tobacco seedlings are: (1) leaves develop a light or pale yellow color, and (2) plants become stunted, showing little growth and vigor. Similar symptoms may develop from a lack of water during dry weather. N deficiency in tobacco seedlings is not common if recommended amounts of N are properly applied to plant beds. However, excessive rainfall may create the need for additional N. Also, the use of ammonium or organic forms of N on plant beds fumigated in the spring may result in N deficiency.
1402001	cold injury (low temperature)		Temperatures near freezing may cause the bud and younger leaves to turn yellow or whitish in color. Leaves may cup upwards and become puckered or elongated. Some varieties are more sensitive to cold injury than others. Plant beds exposed to the north or located in low areas are most susceptible.
1402058	frenching		Frenching is caused by a toxin produced by a nonpathogenic soil bacterium (Bacillus cereus). Yellowing begins along the edge of young leaves and may eventually include all the area between the veins which remain green. Plants are stunted and develop a large number of long, narrow leaves and suckers. Frenching normally occurs in small areas of the field, especially in poorly drained, high pH soils during cool, wet weather.
1402054	bacterial soft rot	Pectobacterium carotovorum ssp. carotovorum	This bacterial soft rot usually first appears following topping and suckering. Although the bacteria can invade the stalk through any wound, they usually enter through the break at the top. The pith rapidly turns brown and collapses in a watery rot. A foul odor is evident as the stalks become hollow. Leaves adjacent to the rotting pith will wilt. The rot may extend into the leaves through the midrib. The midribs turn black and the leaves droop. If infected leaves are placed in the barn, soft rot may continue to develop as barn rot.
1440009	anthracnose	Colletotrichum nicotianae	Symptoms of anthracnose include spotting of the leaves, development of cankers on midribs and veins of leaves, and eventual stunting and/or death of transplants. Leaf spots are at first pinpoint size, water-soaked, and depressed. They enlarge to approximately 3 mm in diameter, are light tan in the center, and have raised dark borders. Veins and midribs are often infected, causing the leaf to become distorted. On plants ready to transplant, large red-brown cankers can develop on the stems and petioles. Severely affected plants are killed. With the aid of a hand lens, fruiting bodies called acervuli can be seen in affected areas. These fruiting bodies produce pink spore masses and may have black bristle-like appendages called setae. The disease is most common in plant beds that are weedy and/or deficient in nitrogen.
1440027	Phoma blight	Phoma exigua var. exigua	Spots are tan colored, with minute dark circular specks present on the surface of the spot. Brown spot and ragged leaf spot may be confused. The presence of distinct, circular, black fruiting bodies (pycnidia), which may be seen under magnification, distinguishes this disease from brown spot. The tissue in the spot may become papery-thin, tearing easily and giving the spot a ragged appearance. This disease is usually of minor importance, showing up late in the season on the lower leaves.
1402042	Southern bacterial wilt	Ralstonia solanacearum (except Race 3 Biovar 2)	The first symptom of this bacterial disease is the drooping of one or two leaves which may recover at night. Only half of a leaf may wilt initially. Leaves on one sides of the plant wilt first, while leaves on the other side appear normal. This unilateral wilting is very characteristic. Affected leaves become light green to yellow and occasionally appear scaled. Eventually most or all of the roots become blackened and decay. Infected roots become soft and slimy if adequate water is present. Tan or brown discoloration develops in the vascular tissue just beneath the bark. Pith and cortex also become discolored when involved. Longitudinal sections through affected stalks have narrow, brown lines in the xylem tissue nearest the pith. A slimy substance often oozes from a stalk cut in cross section. If a stalk segment containing discolored vascular tissue is placed in a clear container of water, milky strands stream from the edge of the tissue.
1440040	Potato Virus Y	Potyvirus PVY	The initial symptom of PVY infection is vein clearing on newly developing leaves. The extent of the vein clearing is intermediate between that caused by TEV and TVMV. Leaves then develop a faint mottling and the characteristic vein banding: dark green bands along the veins with lighter green tissue adjacent. The pattern is more regular than that caused by TVMV. Veinlets and veins may become necrotic on plants infected with severe strains of PVY. This Virus is transmitted from vegetables and weeds to tobacco by migrating aphids.
1402068	lightning		Damage is usually in a circular pattern in the field. Plants nearest the strike will suddenly wilt and may die. Whole plants or individual leaves on plants in the surrounding area may also wilt. Some leaves will have black or shriveled midribs and veins. Areas of lamina may pucker because growth of the midribs or veins is reduced. The stalk may be hollow, or the pith may be disced with irregular separations. The pith remains white which differentiates lightning damage from black shank and hollow stalk.
1402061	weather fleck		Soon after exposure to high levels of atmospheric pollutants, leaves may develop dark green water-soaked spots about 1/10 inch in diameter. Within hours, the spots turn dark brown, sometimes remain brown, but often turn white within 48 hours. Symptoms occur most often in low areas of fields. Plants are most sensitive when growing rapidly (plant bed and 4-6 weeks after transplanting), but symptoms may appear at any stage of growth. In the plant bed or on very sensitive varieties, spots appear over the entire leaf surface but are usually confined to the leaf tips of less sensitive varieties. Occasionally spots coalesce, or a central spot may be surrounded by smaller ones. Weather fleck is often confused with other flecks caused by chemicals, diseases, or nutritional disorders.
1402107	tobacco wireworm	Conoderus vespertinus	Wireworms are thin, yellow-brown, hard-bodies larvae of click beetles that reach ½ - ¾ inch in length. They hatch from eggs laid in the summer, feed on roots of tobacco and other plants, and spend the winter in the soil. The first sign of a wireworm problem may be an uneven stand caused by damage to stems of newly set plants. Plants should be dug up and checked for feeding scars and tunneling in the stem. Sod webworms cause similar damage but generally leave silken webbing on and within the damaged stems.
1440074	herbicides (general)		Triazines are a group of herbicides which include atrazine, cyanazine, propazine, ametryn, prometryn, simazine, and metribuzin. Substituted ureas are a group of herbicides which include linuron, diuron, flometruron, and chloroxuron. Both triazines and urea produce similar symptoms. Injury may be caused foliar or root absorption. Low levels produce mild symptoms which first appear on the tips of the older leaves as a yellowing between the veins. As the degree of injury increases, the areas between the veins turn brown and progress toward the base of the leaf. The leaf will die back from the tips and the edges. Plants will be stunted, but may survive very low level exposure, however, plant death occurs from high level exposure. Foliar exposure can kill the plant, but at low levels, yellow to white areas are formed on the leaf which will turn brown and fall out. Ureas may produce a brighter yellow to white leaf mottling than the triazines. Symptoms of injury from herbicides in the triazine and ureas groups are similar and are difficult to separate.
1402106	tobacco wireworm	Conoderus vespertinus	Wireworms are thin, yellow-brown, hard-bodies larvae of click beetles that reach ½ - ¾ inch in length. They hatch from eggs laid in the summer, feed on roots of tobacco and other plants, and spend the winter in the soil. The first sign of a wireworm problem may be an uneven stand caused by damage to stems of newly set plants. Plants should be dug up and checked for feeding scars and tunneling in the stem. Sod webworms cause similar damage but generally leave silken webbing on and within the damaged stems.
1440073	herbicides (general)		Triazines are a group of herbicides which include atrazine, cyanazine, propazine, ametryn, prometryn, simazine, and metribuzin. Substituted ureas are a group of herbicides which include linuron, diuron, flometruron, and chloroxuron. Both triazines and urea produce similar symptoms. Injury may be caused foliar or root absorption. Low levels produce mild symptoms which first appear on the tips of the older leaves as a yellowing between the veins. As the degree of injury increases, the areas between the veins turn brown and progress toward the base of the leaf. The leaf will die back from the tips and the edges. Plants will be stunted, but may survive very low level exposure, however, plant death occurs from high level exposure. Foliar exposure can kill the plant, but at low levels, yellow to white areas are formed on the leaf which will turn brown and fall out. Ureas may produce a brighter yellow to white leaf mottling than the triazines. Symptoms of injury from herbicides in the triazine and ureas groups are similar and are difficult to separate.
1440059	bacterial black stalk	Erwinia spp.	Bacterial Black Stalk is similar to hollow stalk and occasionally occurs in burley during periods of drought. The bark of the stalk is blackened from the ground upward, but the pith is not destroyed. The leaves are bright yellow with decayed midribs.
1402004	weather fleck		on seedlings is often confused with anthracnose
1402053	charcoal root rot	Macrophomina phaseoli	Plants are usually predisposed to this fungus disease by certain practices such as the application of contact sucker control materials during hot weather. Irregular black lesions may extend from the soil surface to the top of the plant. A basal rotting of plants may occur, although roots are usually not affected . Stalks cut longitudinally exhibit appreciable pith and wood decay. In advanced stages, the pith may completely disappear resulting in a hollow stalk. Leaves of affected plants turn yellow, droop, and die.
1440085	chemicals		Other chemical substances such as oils, solvents, fuels, and diluents may cause injury to tobacco through foliar contact. This contact may result in darkening of tender leaf areas, distortion of the leaf, or the formation of necrotic areas on the leaf. Holes may appear in the leaf if the tissue is killed. Severe exposure may result in the loss of turgor, and/or leaf drop; but under normal circumstances, later growth is not affected.
1440008	blue mold	Peronospora tabacina	Blue mold can be very devastating to tobacco plants in the bed. Usually, the first symptom of blue mold in the bed is yellowed areas of diseased plants. The leaves of affected plants in these yellowed areas will have a cupped appearance, and the undersides of the leaves will show tell-tale, blue-gray downy fungal growth. Older plants can be deformed and twisted, and the main growing point eventually is killed. Veins in affected areas of twisted leaves are reddish-brown and can become necrotic. On older plants, definite yellow spots with bluish fungal growth on the underside of leaves can occur.
1402067	hail		Minor damage consists of small rounded tears in the leaf. Heavier hail may rip the leaves to shreds, break leaves off the stalk, and even break stalks.
1440063	weather fleck		Exposure to high levels of atmospheric pollutants such as ozone may cause tobacco leaves to develop small dark green water-soaked spots. Within 48 hours, the lesions change to a brown color then to grey or white and appear as sunken necrotic areas bordered by chlorotic tissue. Lower leaf surfaces may show no evidence of damage in the early stages. Symptoms may occur at any stage of growth, but most commonly occur during periods of rapid growth. Older leaves are more susceptible. Lesions may coalesce causing the lamina to become necrotic and fall out.
1440025	brown spot	Alternaria alternata	Symptoms of the brown spot fungus first appear on the lower leaves. Spots are brown with sharply defined margins and may be surrounded by yellow halos. The primary distinguishing characteristics of brown spot are the dark concentric rings within spots that give it a target-like appearance. With magnification, reproductive structures of the casual agent are seen as tufts of black fungal spores (conidia). Under severe conditions, spots are numerous, may coalesce, and give the leaf a ragged appearance as the infected tissue falls out.
1402006	Pythium diseases	Pythium spp.	Under severe situations, the plant bed may be bare. Newly transplanted tobacco is vulnerable to damping-off during cool, wet weather. Pythium lesions are large and wet. They extend up the plant tissue or encompass the entire stem.
1440038	Tobacco Streak Virus	Ilarvirus TSV	Streak in burley tobacco follows a typical pattern wherein vigorously growing plants suddenly develop a severe necrotic streaking of the bud leaves and stalk. The stalk is marked by a depressed dark area, and the midveins of the leaves have dead streaks in them. The leaves curl downward, are distorted, wilted, and usually chlorotic. When death of the affected plant seems imminent, growth resumes from the bud with resulting leaves appearing normal except for occasional faint mottling. Leaves damaged early are permanently dwarfed and exhibit numerous necrotic areas. The virus is common in sweet clover and is presumably moved to tobacco by an insect, probably by thrips.
1440026	Phoma blight	Phoma exigua var. exigua	Spots are tan colored, with minute dark circular specks present on the surface of the spot. Brown spot and ragged leaf spot may be confused. The presence of distinct, circular, black fruiting bodies (pycnidia), which may be seen under magnification, distinguishes this disease from brown spot. The tissue in the spot may become papery-thin, tearing easily and giving the spot a ragged appearance. This disease is usually of minor importance, showing up late in the season on the lower leaves.
1402046	southern blight	Sclerotium rolfsii	With this fungal disease, leaves of infected plants rapidly turn yellow, wilt, and die. The dried, brown leaves hang down the dying stalk. The root system remains healthy prior to the death of the plant. Infected plants are usually scattered singly through the field or occur in small groups. Symptoms may be confused with those of black shank. During warm, moist weather, the fungus produces a white cottony growth from the discolored stalk lesions. Discing of the pith similar to black shank may occur, but it is much lighter in color and not as well-organized. Infected stalks easily break at the stalk lesion.
1402052	charcoal root rot	Macrophomina phaseoli	Plants are usually predisposed to this fungus disease by certain practices such as the application of contact sucker control materials during hot weather. Irregular black lesions may extend from the soil surface to the top of the plant. A basal rotting of plants may occur, although roots are usually not affected . Stalks cut longitudinally exhibit appreciable pith and wood decay. In advanced stages, the pith may completely disappear resulting in a hollow stalk. Leaves of affected plants turn yellow, droop, and die.
1402049	Rhizoctonia damping-off, blight and rot	Rhizoctonia solani	This soil-borne fungus infects the lower stem of the tobacco plant. Symptoms begin on seedlings and transplants as a dark brown lesion on the stem near or below ground level. Lesions vary in size and number depending on environmental conditions. In wet, cool weather, the lesions may enlarge upward and around the stem until the plant falls over. This may be confused with black shank or Pythium damping-off. On older plants, a dark brown lesion up to several inches long occurs at or near the soil line. It may girdle the stalk which becomes hard and brittle. The stalk may break at this lesion. The plant may be stunted with yellow to brown and/or wilted leaves. Roots usually show no evidence of decay.
1440119	tobacco hornworm	Manduca sexta	The tobacco tomato hornworms, Manduca sexta (Linnaeus), and Manduca quinquemaculata (Haworth), are potentially the most destructive insect pests of tobacco. They chew irregular holes in leaves and often feed along leaf margins. Newly hatched larvae are 1/4-inch long, pale green with a large horn at the posterior end. Larger larvae (up to 4 inches) are bright green in color. The tobacco hornworm larva has seven white diagonal stripes on each side and a curved red horn. The adult, a dark gray moth, has six round, orange-yellow spots on each side of the abdomen. Tomato hornworms have eight V-shaped marks on each side and the horn is straighter and blue-black.
1440117	tobacco hornworm	Manduca sexta	The tobacco tomato hornworms, Manduca sexta (Linnaeus), and Manduca quinquemaculata (Haworth), are potentially the most destructive insect pests of tobacco. They chew irregular holes in leaves and often feed along leaf margins. Newly hatched larvae are 1/4-inch long, pale green with a large horn at the posterior end. Larger larvae (up to 4 inches) are bright green in color. The tobacco hornworm larva has seven white diagonal stripes on each side and a curved red horn. The adult, a dark gray moth, has six round, orange-yellow spots on each side of the abdomen. Tomato hornworms have eight V-shaped marks on each side and the horn is straighter and blue-black.
1440082	glyphosate		Glyphosate is a systematic herbicide that causes damage to tobacco within five to seven days after exposure. Injury first appears as a light yellow discoloration in the newly developing leaves. The leaf color changes from green to pale yellow and/or white from the base of the leaf to the tip. After exposure, newly formed leaves will be narrow and margins will be curled downward. Symptoms on mature leaves consist of areas of yellow or brown tissue between the veins while the remainder of the leaf looks normal. The yellow or brown interveinal area will frequently die and fall out leaving a shot- hole appearance. Higher exposure rates will cause death of the plant in seven to fourteen days after symptoms appear.
1440083	herbicides (general)		Exposure of tobacco to contact herbicides such as paraquat and dinoseb causes white lesions on leaves and stems. The lesions turn brown and may fall out, leaving holes in the leaf. Low levels of exposure produce distinct individual lesions. At higher exposure levels, the lesions combine, causing the leaves to yellow and areas between the veins to die and fall out. If the plant does not die from the exposure, later growth will be normal. Weather fleck, contact injury by other herbicides, and some types of chemicals produce similar symptoms.
1402050	Rhizoctonia damping-off, blight and rot	Rhizoctonia solani	This soil-borne fungus infects the lower stem of the tobacco plant. Symptoms begin on seedlings and transplants as a dark brown lesion on the stem near or below ground level. Lesions vary in size and number depending on environmental conditions. In wet, cool weather, the lesions may enlarge upward and around the stem until the plant falls over. This may be confused with black shank or Pythium damping-off. On older plants, a dark brown lesion up to several inches long occurs at or near the soil line. It may girdle the stalk which becomes hard and brittle. The stalk may break at this lesion. The plant may be stunted with yellow to brown and/or wilted leaves. Roots usually show no evidence of decay.
1440125	grasshoppers		Grasshoppers [various species including differential grasshopper, Melanoplus differntialis (Thomas) and redlegged grasshopper, Melanoplus femurrubrum (DeGeer)] chew irregular holes between veins of leaves. Adult redlegged grasshoppers are 3/4 to 1 inch long. They are greenish-gray to olive-green or reddish-brown with a yellowish underside. The hind tibiaae are red with black spines. The differential grasshopper is 1 1/2 to 2-inches long with a shiny, brownish-yellow color and black V-shaped marks on the outer face of the yellow femur. Immature (nymphs) are similar but lack fully developed wings. Most species prefer other plants but will eat tobacco if their food supply is inadequate. Grasshoppers often migrate into tobacco fields from ditch banks and grasslands, especially when populations are high during droughts and following hay mowing or other habitiat modifications. Tobacco injury usually starts along the edges of fields and is more common late in the growing season.
1440084	chemicals		Xylene is a chemical carrier that is present in some emulsifiable concentrate pesticides. When high rates of pesticides containing this chemical are applied under high pressure to young tobacco leaves, injury similar to a mild case of 2,4-D injury may be sustained. Leaves affected by xylene are slightly narrower than normal and may have a glossy appearance. Though similar to 2,4-D injury leaves affected by xylene are not as stiff.
1440037	Cucumber Mosaic Virus	Cucumovirus CMV	The symptoms of CMV infection are quite striking and resemble those caused by other aphid-borne viruses and tobacco mosaic virus. Typical symptoms are mottling or mosaic of the young leaves, sometimes accompanied by stunted, narrow, or distorted older leaves. Scalding of infected leaves may also occur. Cucumber mosaic virus is transmitted by aphids migrating from infected weeds and vegetable crops. CMV is relatively rare in burley.
1440034	Tobacco Etch Virus	Potyvirus TEV	The first symptom of TEV infection is a pronounced vein clearing on expanding leaves. This is followed by necrosis of a thin line of tissue along the veins, resulting in an etched pattern. Subsequently, young leaves develop a mosaic which fades to mottling as the leaf ages. Etching and more pronounced veinal necrosis is common. Plant growth is retarded, resulting in stunting, especially when young plants are infected. The virus overwinters in perennial solanaceous weeds and is transmitted to tobacco by migrating aphids. TEV often occurs in combination with other aphid-borne viruses. Tobacco etch is one of the most common virus diseases of burley.
1440118	tobacco hornworm	Manduca sexta	The tobacco tomato hornworms, Manduca sexta (Linnaeus), and Manduca quinquemaculata (Haworth), are potentially the most destructive insect pests of tobacco. They chew irregular holes in leaves and often feed along leaf margins. Newly hatched larvae are 1/4-inch long, pale green with a large horn at the posterior end. Larger larvae (up to 4 inches) are bright green in color. The tobacco hornworm larva has seven white diagonal stripes on each side and a curved red horn. The adult, a dark gray moth, has six round, orange-yellow spots on each side of the abdomen. Tomato hornworms have eight V-shaped marks on each side and the horn is straighter and blue-black.
1402048	southern blight	Sclerotium rolfsii	The base of the stalk shows a brown, sunken lesion or dead area, lighter in color than the stalk lesion caused by black shank. The dead area is stingy, and the outer layer of stalk often has a papery consistency.
1402127	tobacco hornworm	Manduca sexta	Tobacco and tomato hornworms [Manduca sexta (Linnaeus), Manduca quinquemaculata (Hawthorn)]: These two species, usually referred to collectively as "hornworms," are potentially the most destructive insect pests of tobacco. Newly hatched larvae are ¼ inch long, pale green with a large horn at the posterior end. Larger larvae (up to 3 or 4 inches) are bright green in color. Tobacco hornworm larvae have seven white diagonal stripes on each side and a curved red horn. Tomato hornworms have eight white V-shaped marks on each side and the horn is straighter and blue-black. Small larvae chew small irregular holes in leaves. Larger larvae more often feed on leaf margins and may leave only the midribs of leaves.
1440124	stalk borer	Papaipema nebris	The stalk borer is recognized by prominent longitudinal white stripes at the head and posterior ends of the body. The stripes are interrupted by a distinct dark purple "saddle" approximately 1/3 of the distance back from the head. Full- grown larvae are about 1 to 1 1/2 inches long. Stalk borers may be found feeding on foliage or boring into the stalk of tobacco plants, usually during late June to early July. Infestations are more likely to occur along weedy field margins.
1440123	stink bugs		Stink bugs [several species including green, Acrosternum hilare (Say); southern green, Nezara viridula (Linnaeus), and brown, Euschistus servus (Say)] are green or gray-brown, shield shaped bugs slightly over 1/2 inch long when full grown. Young (nymphs) are similar to adults but are smaller and lack wings. Their beak-like mouthparts are used to remove plant sap. A salivary secretion, which is injected as the insect feeds, produces a rapid wilting of the leaf or stem. The leaf usually resumes its normal shape and is not permanently damaged. Scalded areas may develop on injured leaves during hot weather. Growers are likely to encounter injury symptoms and not see the insects. Damage is usually limited to scattered plants, often in border rows. Some stink bugs are beneficial insects. They resemble plant-feeding stink bugs but can be identified by the presence of a distinct spine on each "shoulder".
1440081	herbicides (general)		Tobacco is extremely sensitive to picloram and very small amounts from drift, contaminated equipment, or residue in the soil will cause serious injury. The most common symptom is a downward curling of the margins and tips of the leaf. The curl of the tip results in "parrott beak" or hooded appearance. Symptoms appear first on young growing leaves, but due to the persistence of the compound, it will continue to affect the new bud leaves. New leaves may take on a heart-shaped appearance as the midrib is stunted, while the adjoining tissue continues to grow. Higher rates of picloram result in thick, strappy, elongated older leaves and elongated or aborted bud leaves. Young leaves may also have a wide thick midrib with little or no adjoining leaf tissue. Picloram residues may persist in the soil and cause damage to tobacco for periods of three or more years after application.
1402047	southern blight	Sclerotium rolfsii	The fungus produces small, round structures (sclerotia) on the surface of the stalk lesion. These are white at first, turning brown with maturity, and resemble mustard seed.
1440122	stink bugs		Stink bugs [several species including green, Acrosternum hilare (Say); southern green, Nezara viridula (Linnaeus), and brown, Euschistus servus (Say)] are green or gray-brown, shield shaped bugs slightly over 1/2 inch long when full grown. Young (nymphs) are similar to adults but are smaller and lack wings. Their beak-like mouthparts are used to remove plant sap. A salivary secretion, which is injected as the insect feeds, produces a rapid wilting of the leaf or stem. The leaf usually resumes its normal shape and is not permanently damaged. Scalded areas may develop on injured leaves during hot weather. Growers are likely to encounter injury symptoms and not see the insects. Damage is usually limited to scattered plants, often in border rows. Some stink bugs are beneficial insects. They resemble plant-feeding stink bugs but can be identified by the presence of a distinct spine on each "shoulder".
1440120	tobacco thrips	Frankliniella fusca	Tobacco thrips may cause damage to tobacco, especially during dry years. These slender yellow-to-brown insects are about 1/25 inch long. Adults have four very narrow, featherlike wings. Adults and nymphs suck sap from the leaves producing gray to silver feeding marks primarily along the veins of the lower leaves. The leave also become peppered with minute black spots. The underside of midribs may be damaged. Heavy infestations cause the foliage to turn yellow.
1440035	Tobacco Vein Mottling Virus	Potyvirus TVMV	The initial symptom of TVMV infection is a slight, barely visible clearing on expanding leaves. Subsequently, leaves develop irregular green patterns of mottling adjacent to the veins; this is most evident on the ruffles at the base of older leaves. Chlorosis of infected leaves is extensive, giving the plants a pale green or yellow appearance which may be evident from a distance. Necrotic spotting of the leaf, indistinguishable from weather fleck, may develop and become increasingly prevalent as plants mature. The earlier that plants are infected with the virus, the greater the damage. The virus overwinters in perennial solanaceous weeds and is transmitted to tobacco by aphids. The virus is often found in combination with TEV. TVMV is also one of the most prevalent viruses in burley.
1440105	variegated cutworm	Peridroma saucia	The variegated cutworm, may be a serious problem during the mid- portion of the growing season. This climbing cutworm usually feeds in the buds and on the leaves of tobacco plants. Larvae vary widely in color. The posterior segment is enlarged and blunt. A row of whitish or yellowish dots is visible down the middle of the back. The full grown larva usually has a mark on the back of the eighth abdominal segment, followed by a conspicuous yellow or orange area. There is usually a narrow orange-brown stripe on the sides. The variegated cutworm passes the winter in the pupal stage.
1440036	Tobacco Vein Mottling Virus	Potyvirus TVMV	The initial symptom of TVMV infection is a slight, barely visible clearing on expanding leaves. Subsequently, leaves develop irregular green patterns of mottling adjacent to the veins; this is most evident on the ruffles at the base of older leaves. Chlorosis of infected leaves is extensive, giving the plants a pale green or yellow appearance which may be evident from a distance. Necrotic spotting of the leaf, indistinguishable from weather fleck, may develop and become increasingly prevalent as plants mature. The earlier that plants are infected with the virus, the greater the damage. The virus overwinters in perennial solanaceous weeds and is transmitted to tobacco by aphids. The virus is often found in combination with TEV. TVMV is also one of the most prevalent viruses in burley.
1440018	blue mold	Peronospora tabacina	Blue mold may occur on the plant anytime from seedling to harvest; however, young tissue is more susceptible than old tissue. The first evidence of blue mold in the field usually occurs on the leaves as yellow circular spots about the size of a nickel. The spots soon develop the characteristic bluish, downy fungal growth on the undersides of the leaves which is best seen in the morning when the leaf is wet. If spots develop on leaves that are expanding, a puckering of the leaf occurs. As spots age, they turn from yellow to tan or brown and often tear or drop out. If infection has occurred near or on a leaf vein, a localized systematic infection may occur. The affected vein becomes reddish-brown, and the area around the vein is yellowed and distorted. In newly set transplants, it is possible for the fungus to develop systematically, killing the main bud and resulting in stunting or death of the plant. Splitting the stalk of systematically infected plants reveals a reddish- brown discoloration in the vascular tissue beneath the epidermis. A one-sided systemically infection also occur, resulting in a deformed stalk and lodging of affected plants. During weather favorable for blue mold (cool, cloudy, and wet), the disease can develop rapidly, causing numerous leaf lesions which can result in leaf blighting and severe leaf loss. The disease may develop during hot, humid periods if cool nights exist.
1402051	black root rot	Thielaviopsis basicola	This fungal disease is associated with high soil pH. In the plant bed, irregular areas of seedlings turn pale green to yellow. Roots may be severely blackened, rotted or pruned, or they may have only a few lesions near the tap root. Damping-off can occur if the rot extends up the stem. In the field, infected plants in circular areas turn pale, are stunted, and flower prematurely. They wilt in the heat of the day but recover at night. Small roots may be rotted at the tips; larger ones have rough sunken black lesions along their length. Root pruning is common. If the weather turns warm before rot becomes extensive, new roots will form and plants will recover. Symptoms may be confused with those due to drowning, lesion nematode, or black shank.
1440062	weather fleck		Exposure to high levels of atmospheric pollutants such as ozone may cause tobacco leaves to develop small dark green water-soaked spots. Within 48 hours, the lesions change to a brown color then to grey or white and appear as sunken necrotic areas bordered by chlorotic tissue. Lower leaf surfaces may show no evidence of damage in the early stages. Symptoms may occur at any stage of growth, but most commonly occur during periods of rapid growth. Older leaves are more susceptible. Lesions may coalesce causing the lamina to become necrotic and fall out.
1402138	green lacewings	Chrysopa spp.	Both the adult and immature forms of these beneficials are predators on aphids. The immatures are often known as aphid-lions. Lacewing eggs are unusual in that they are attached to surfaces by long, threadlike, upright stalks. Larvae are shaped somewhat like those of lady beetles but are light colored and have a pair of long sickle-shaped mouthparts protruding forward. Adults are light green, about 5/8 inch long and have 4 large lacy wings, thin bodies and long antennae.
1402091	chemicals		Flumetralin (Prime +®) is applied at the late button to early flower stage of plant development to prevent sucker growth. If applied earlier, the tip leaves not removed by topping may exhibit symptoms similar to those caused by mosaic virus. There will be splotches of light and dark green leaf tissue. These young leaves may curl downward and do not fully expand. Buds of immature plants and affected suckers may cease growth. The tip end of the two outer leaves of each sucker may bend outward. Yellow residue of the chemical may be observed for several days after application. Occasionally, pith tissue will differentiate into adventitious buds, which appear as clusters of very small suckers. Suckers that escape contact with Prime+® will continue to grow.
1402084	glyphosate		Glyphosate is a systemic herbicide that will produce injury in 5 to 7 days after exposure to the foliage. Injury frirst appears as a light yellow discoloration in the newly developing leaves. Leaf color changes from green to pale yellow and/or white from the base of the leaf to the tip. Newly formed leaves will be narrow, and the margins will be curled downwards. Symptoms on mature leaves will consist of areas of yellow or brown tissue between the veins while the remaining area of the leaf is normal. Dead areas will fall out, resulting in a "shot-hole" appearance. Areas around the veins will often be green with a yellow discoloration between the veins. Actively growing plants will die after exposure to glyphosate.
1402113	stink bugs		Young (nymphs) are similar to adults but are smaller and lack wings. Eggs are barrel-shaped and laid in clusters on the underside of leaves. Both adults and nymphs suck plant juices through beak-like mouthparts. They will attack all plant parts but prefer young, tender growth. This may cause one or more leaves to wilt and flop over, similar to sunscald.
1402030	Potato Virus Y	Potyvirus PVY	Mild symptoms of this virus disease include leaf mottling and crinkling, prominent veins, and curved midribs. Leaf tissue, except for that around the veins, turns slightly yellow in color. This gives the veins a green-banded appearance. As the leaves mature, sunken brown spots may develop on the upper surface of the midrib. Systematic necrosis frequently occurs in cultivars resistant to root-knot nematodes. As lower leaves begin to ripen, midribs may turn black; leaves may die and fall from the stalk. If the stalk is split, areas of black discoloration will be found extending from top to bottom of the plant.
1402044	Fusarium wilt	Fusarium oxysporum f.sp. nicotianae	This fungal disease causes slow yellowing and drying of the leaves. Symptoms are usually more pronounced on one side of the plant. Leaves may not wilt at first, but those on affected sides of the plants are usually stunted. The top of the plant may be drawn toward the diseased side. Wilting eventually occurs and upper leaves have a bronze cast. On the affected side of the plant, wood beneath the outer bark has a uniform chocolate brown discoloration. Such discoloration can also be seen in the midribs of affected leaves and in roots. Some roots on the affected side die. The unilateral appearance of symptoms and vascular discoloration can cause confusion between Fusarium wilt and Granville wilt. However, the "bacterial streaming" described for Granville wilt is a reliable way to distinguish between these two diseases. Fusarium wilt is frequently accompanied by root-knot nematode infection.
1402086	herbicides (general)		Exposure to contact herbicides such as paraquat and dinoseb causes white lesions on leaves and stems. Other herbicides such as triazines, hexaxinone, acifluorfen, and bentazon may damage tobacco by root absorption, as well as by contact injury. The lesions turn brown and may fall out leaving holes in the leaf. Low levels of paraquat produce distinct individual lesions. With high levels, the lesions combine causing the leaves to yellow, and areas between the veins to die and fall out. If the plant does not die, later growth will be normal. Weather fleck and some types of chemicals may produce similar symptoms.
1402135	convergent lady beetle	Hippodamia convergens	Both adult and larval lady beetles are important predators of aphids. Adults can consume 50 aphids per day, while larvae kill 10 to 25 per day. Adult convergent lady beetles are black with orange or red wing covers with 12 black spots (spots are sometimes indistinct). The pronotum has two converging lines and a white margin.
1402112	stink bugs		Stink bugs are green or brown, shield-shaped bugs slightly over ½ inch long when full grown.
1440032	Tobacco Etch Virus	Potyvirus TEV	The first symptom of TEV infection is a pronounced vein clearing on expanding leaves. This is followed by necrosis of a thin line of tissue along the veins, resulting in an etched pattern. Subsequently, young leaves develop a mosaic which fades to mottling as the leaf ages. Etching and more pronounced veinal necrosis is common. Plant growth is retarded, resulting in stunting, especially when young plants are infected. The virus overwinters in perennial solanaceous weeds and is transmitted to tobacco by migrating aphids. TEV often occurs in combination with other aphid-borne viruses. Tobacco etch is one of the most common virus diseases of burley.
1440041	Alfalfa Mosaic Virus	Alfamovirus AMV	The most distinguishing symptom of alfalfa mosaic virus is a bright yellow mosaic of the affected leaves, however, not all strains of the virus produce this symptom. Chlorotic line patterns similar to the symptoms of tobacco ringspot are common. Chlorotic blotches and vein clearing of expanding leaves are often present. The virus overwinters in legumes and is transmitted to tobacco by aphids. AMV is found infrequently in burley.
1402096	calcium deficiency		Calcium (Ca)deficiency seldom occurs under field conditions, but some varieties cannot supply sufficient Ca to buds and young leaves during periods of rapid growth even though soil Ca is adequate for normal growth of other varieties. Initially, Ca deficient buds are twisted with downward curling of leaf margins and downward hooking of leaf tips. As leaf expansion continues, these symptoms become more pronounced, with separations of margin tissue which give the leaf a scalloped appearance. Tip and margin tissues become chlorotic and tips cease growing, giving the leaf a stubby appearance. Ca deficient leaves are thicker and sometimes greener than normal leaves. Symptoms become progressively less pronounced on older leaves and seldom occur at the lower stalk positions.
1402060	drowning		Plants may wilt or "flop" a few hours after a rain, especially in areas with poor soil drainage. Yellowing, starting with the lower leaves, may follow if the flooded conditions persist. The lower leaves may eventually die, while the bud remains green. Apparent injury may be more severe on older than on younger plants. Deep roots may be killed, so the tobacco develops a shallow root system. Partial drowning may result in stunted plants and premature flowering.
1402059	frenching		Frenching is caused by a toxin produced by a nonpathogenic soil bacterium (Bacillus cereus). Yellowing begins along the edge of young leaves and may eventually include all the area between the veins which remain green. Plants are stunted and develop a large number of long, narrow leaves and suckers. Frenching normally occurs in small areas of the field, especially in poorly drained, high pH soils during cool, wet weather.
1402080	herbicides (general)		Injury symptoms from dicamba and picloram are identical but tobacco is much more sensitive to pircloram. Symptoms are somewhat similar to 2,4-D. Young leaves are often strapped, while the edges and tips of the leaves curl downward, giving a "parrot-beak" or "cobra-head" appearance. A small pointed tip usually protrudes from the end of the leaf. Leaf margins are not serrated as is common with 2,4-D. Severe injury is characterized by strapped and stubby young leaves. Bud leaves are often short and stubby with rounded tips.
1402085	herbicides (general)		Exposure to contact herbicides such as paraquat and dinoseb causes white lesions on leaves and stems. Other herbicides such as triazines, hexaxinone, acifluorfen, and bentazon may damage tobacco by root absorption, as well as by contact injury. The lesions turn brown and may fall out leaving holes in the leaf. Low levels of paraquat produce distinct individual lesions. With high levels, the lesions combine causing the leaves to yellow, and areas between the veins to die and fall out. If the plant does not die, later growth will be normal. Weather fleck and some types of chemicals may produce similar symptoms.
1402002	fertilization		Excessive rates of fertilizer, especially soluble salts and nitrogen and potassium, can result in seedling injure indicated by slow or irregular plant growth, yellowing or "burning" of leaves, and death of plants in patches. Whitish fertilizer residues may be noted on the soil surface. Stem necrosis sometimes occurs near the soil line. Symptoms are more acute in dry soil.
1402028	Potato Virus Y	Potyvirus PVY	Mild symptoms of this virus disease include leaf mottling and crinkling, prominent veins, and curved midribs. Leaf tissue, except for that around the veins, turns slightly yellow in color. This gives the veins a green-banded appearance. As the leaves mature, sunken brown spots may develop on the upper surface of the midrib. Systematic necrosis frequently occurs in cultivars resistant to root-knot nematodes. As lower leaves begin to ripen, midribs may turn black; leaves may die and fall from the stalk. If the stalk is split, areas of black discoloration will be found extending from top to bottom of the plant.
1402111	tobacco thrips	Frankliniella fusca	Thrips feeding usually follows minor veins and the overall appearance is similar to some diseases like etch. Heavy feeding will sometimes give the surface of the leaf a shiny or silvery appearance. The underside of midribs may also be injured. Damage is most common on lower leaves of knee-high plants, but thrips may attack newly set plants. Adult thrips are tiny (1/25 inch), elongate insects, dark brown with featherlike wings. Immature are smaller and yellow or yellow-orange. To see thrips, slap a damaged leaf against a light-colored surface and observe insect movement on that surface. Thrips may be most significant as a vector of tomato spotted wilt virus.
1402077	herbicides (general)		Injury from phenoxy herbicides, such as 2,4-D, causes symptoms that depend on herbicide rate and age of tobacco. Young leaves are puckered and stiff, with very prominent midribs. The tips and margins of the leaves are often serrated. Higher dosages cause strappy leaves with parallel veins and twisted stems. On older plants, and the midrib also bends downward.
1402074	herbicides (general)		Triazines are a group of herbicides which include atrazine, cyanazine, propazine, ametryn, prometryn, simazine, and metribuzin. Substituted ureas are a group of herbicides which include linuron, diuron, fluometuron, and chloroxuron. Both triazines and ureas produce similar injury symptoms. Injury can be caused by foliar or root uptake. Mild symptoms from low levels first appear on the tips of older leaves as yellowing between the veins. As the injury increases, the areas between the veins turn brown and progress toward the base of the leaf. The leaves will die back from the tips and edges. Plants will be stunted but may survive from very low levels; however, plant death will occur from high levels. Foliar exposure can kill the plant; however, with low levels, yellow to white areas are formed, turn brown, and fall out. Ureas may produce a brighter yellow to white leaf mottling than triazines. Symptoms of injury from all herbicides in the triazine and urea groups are very similar and are difficult to separate.
1402082	herbicides (general)		Injury symptoms from dicamba and picloram are identical but tobacco is much more sensitive to pircloram. Symptoms are somewhat similar to 2,4-D. Young leaves are often strapped, while the edges and tips of the leaves curl downward, giving a "parrot-beak" or "cobra-head" appearance. A small pointed tip usually protrudes from the end of the leaf. Leaf margins are not serrated as is common with 2,4-D. Severe injury is characterized by strapped and stubby young leaves. Bud leaves are often short and stubby with rounded tips.
1402071	chemicals		Xylene is a chemical carrier present in some emulsifiable concentrate pesticides. When high rates of pesticides containing this chemical are applied under high pressure to young tobacco leaves, injury is very similar to a mild case of 2,4-D injury. The leaves are slightly narrower than normal and may have a glossy appearance, but are not as stiff as those with 2,4-D injury.
1440076	chemicals		Small irregular, oval- shaped lesions with a white-tan to brown-yellow appear on the margins of the bottom leaves. The lesions may progress to involve the entire interveinal area of the leaf as well as move up the plant, especially under dry conditions. With high concentrations of the chemical, the leaf edges may cup upward or curl downward, and the leaves may be narrow and arrow shaped. Stunting of the plants and premature flowering may also occur. Injury symptoms may be similar to those of manganese toxicity or triazine herbicide damage. Recommended rates and proper application may produce a mild flecking but rarely causes serious injury.
1402087	chemicals		Fatty alcohols turn smaller suckers brown soon after application. Leaf axils may also be burned by high concentrations of the chemical. Occasionally, buds of young plants may be killed. There may be contact-type burns on the tender, upper leaves. Damage is usually minor, but can be more severe if the concentration of the chemical is excessive or if application is made to wilted plants. Usually there will be burns along the edge or other portions of the leaf where the spray material collects. Leaf drop may occur at the lower part of the stalk if burn in the leaf axil is substantial, leaves are large, humidity is high, and certain disease organisms are present. Excessive nitrogen fertilizer contributes to these conditions.
1402088	chemicals		Maleic hydrazide, applied after topping to prevent sucker growth, inhibits cell division. If applied to immature plants, the younger leaves become narrow and pale green. Stalk elongation is slowed or halted. Application rate affects the degree of response. Applied at the correct rate and stage of plant development, the chemical has little visible effect on harvestable leaves, except for a slight yellowing of the upper leaves. Existing suckers at the time of treatment develop small, narrow leaves and are limited to growth. Suckers tend to develop at the bottom of the stalk as harvest nears completion. Excess rates will cause considerable yellowing, thickening, and drooping of the tip leaves.
1402137	syrphid or flower flies		Syrphid larvae [Allograpta oblique (Say) and others]: Syrphid larvae are greenish or brownish maggots that are predators of aphids. The larva has an indistinct tapering head with mouth hooks on the anterior end. A pair of dorsal tracheal trunks, visible through the thin skin, make this maggot appear to have two longitudinal stripes along its back. Larvae feed on aphids by sucking out their body fluids. Depending on the species, a larva can consume 100-900 aphids during its lifetime. The brown pupal case is tear-drop shaped with a prominent tube at the posterior end. The adult flies are brightly colored, wasp-like insects with bands across their abdomen. They are often seen hovering over plants. Syrphid flies have one pair of wings, while wasps have two pairs.
1440010	nitrogen deficiency		Nitrogen (N) deficiency; The two most common symptoms of N deficiency in tobacco seedlings are: (1) leaves develop a light or pale yellow color, and (2) plants become stunted, showing little growth and vigor. Similar symptoms may develop from a lack of water during dry weather. N deficiency in tobacco seedlings is not common if recommended amounts of N are properly applied to plant beds. However, excessive rainfall may create the need for additional N. Also, the use of ammonium or organic forms of N on plant beds fumigated in the spring may result in N deficiency.
1402065	sandblasting		Windblown sand may cause physical damage to young transplants on the side of the plant toward the prevailing wind. Mild symptoms include some death of tissue between lateral veins of the lower leaves. More severe damage results in entire leaves being killed and stalks being destroyed down to the woody layer. Some plants may be killed and others may be covered by sand. Soil texture and moisture, wind intensity and duration, presence of plant residue on the soil surface, and windbreaks will determine the extent of the damage.
1402037	Phytophthora blight	Phytophthora nicotianae	The black shank fungus can infect tobacco plants of any age. In young seedlings, stems may decay near the soil surface and the root system may become partly or completely black. A dark lesion may extend up the stem. Symptoms are sometimes confused with damping-off caused by other organisms. The photo above shows black shank damage as it appears in the field. Leaves may suddenly and uniformly wilt or droop, turn yellow, and hang down the stalk. Warm, moist weather conditions favor black shank development. Advanced stages of this disease may cause partial or complete decay of the root system. The black shank fungus is soil-borne and is readily translocated by equipment or water movement to noninfested areas. Since the spores of the fungus are so mobile, distribution of the disease within a field may not be uniform.
1402090	chemicals		Chlorpropham (Bud Nip®) is used for the prevention of late season suckers. It is applied to plants with fully expanded tip leaves. If applied earlier, the upper leaves exhibit more puckering than normal, which gives the leaves a "waffled" appearance. Suckers present at the time of treatment grow slowly and develop a rosette appearance, apparently because internode lengths are shortened.
1440093	nutrient excess or toxicity (general)		Visual symptoms of Mn toxicity may develop when soil acidity reduces the soil pH to near 5.4 or less. Under these conditions, the lower leaves take on a mottled or chlorotic appearance. Light, greenish-yellow to pale white mottles occur between dark green areas along the veins. Also, leaves may appear to have a hard semi-glossy surface. If the soil pH continues to drop, mottles may be spread over the entire plant and growth will be stunted. Under extremely acid conditions, the availability of Mn increases and plants take up the nutrient to the extent that it becomes toxic, and plants may eventually die. Plants exhibiting Mn toxicity symptoms usually occur in spots or streaks within the field. Seldom will the entire field be affected. The problem is corrected with the proper use of lime.
1440071	lightning		Injured plants show a darkened area from the ground upward along one side of the stalk into the midribs of the leaves. Affected portions of the veins turn black and shrink, giving the leaf a puckered or gathered appearance. The roots do not show evidence of injury. If a stalk is split after it has dried somewhat. It may be hollow, or the pith may be separated into colorless discks with a layered effect. The pith remains white which differentiates lightning damage from black shank. Some plants in the center of the strike area may be killed, with less severe injury in scattered plants. Lightning injury is often mistaken for disease damage.
1402066	soil compaction		Fields with sandy topsoils may develop hard, compacted zones at or just beneath the plow layer. These compacted zones (often called plow-pans, tillage pans, or hardpans) develop when heavy implements are used on wet or recently plowed soil. The compacted layers become hard upon drying and may be detected by probing. Root growth is limited primarily to the upper topsoil and plants may wilt under slight moisture stress. Nutrient uptake, plant growth, and yields may be reduced. Use of implements such as subsoilers or chisel plows to break the compacted zone before transplanting may increase yields 5-20%, depending on the strength of pan development and adequacy of rainfall.
1440072	lightning		Injured plants show a darkened area from the ground upward along one side of the stalk into the midribs of the leaves. Affected portions of the veins turn black and shrink, giving the leaf a puckered or gathered appearance. The roots do not show evidence of injury. If a stalk is split after it has dried somewhat. It may be hollow, or the pith may be separated into colorless discks with a layered effect. The pith remains white which differentiates lightning damage from black shank. Some plants in the center of the strike area may be killed, with less severe injury in scattered plants. Lightning injury is often mistaken for disease damage.
1440012	fertilization		Fertilizer injury results from high concentrations of soluble salts and is most pronounced during periods of dry weather. Under such conditions, plants become dehydrated and wilt, develop a yellow color with browning or burning along leaf margins, and may eventually die. Also, a white coating may occur on the soil where fertilizer salts carried to the surface by evaporating water. Seedling injury may result from effects of fertilizers other than salt concentration. For example, ammonia produced from excessive amounts of ammonium fertilizer may cause injury similar to that caused by soluble salts. The use of organic fertilizers has been found to cause damage to stems of young seedlings at or near soil surface. Where high concentrations of soluble salts occur, through watering of the plant bed for two or three consecutive days will usually correct the condition
1440070	lightning		Injured plants show a darkened area from the ground upward along one side of the stalk into the midribs of the leaves. Affected portions of the veins turn black and shrink, giving the leaf a puckered or gathered appearance. The roots do not show evidence of injury. If a stalk is split after it has dried somewhat. It may be hollow, or the pith may be separated into colorless discks with a layered effect. The pith remains white which differentiates lightning damage from black shank. Some plants in the center of the strike area may be killed, with less severe injury in scattered plants. Lightning injury is often mistaken for disease damage.
1402038	Phytophthora blight	Phytophthora nicotianae	Stalks generally develop black lesions which may extend several inches above the ground
1402032	Tobacco Etch Virus	Potyvirus TEV	Symptoms vary depending on the strain of the virus present and the conditions of plant growth. Veinclearing (lightening of the tissue in and around veins) is followed by a faint, light-green mottling of the leaf. This mottling is similar to that observed with tobacco mosaic; but with etch, the blotches are much less pronounced. Older infected leaves may show a stippled pattern of numerous, small, white flecks and fine lines (etchings), especially along veins.
1402089	chemicals		Maleic hydrazide, applied after topping to prevent sucker growth, inhibits cell division. If applied to immature plants, the younger leaves become narrow and pale green. Stalk elongation is slowed or halted. Application rate affects the degree of response. Applied at the correct rate and stage of plant development, the chemical has little visible effect on harvestable leaves, except for a slight yellowing of the upper leaves. Existing suckers at the time of treatment develop small, narrow leaves and are limited to growth. Suckers tend to develop at the bottom of the stalk as harvest nears completion. Excess rates will cause considerable yellowing, thickening, and drooping of the tip leaves.
1440094	nutrient excess or toxicity (general)		Visual symptoms of Mn toxicity may develop when soil acidity reduces the soil pH to near 5.4 or less. Under these conditions, the lower leaves take on a mottled or chlorotic appearance. Light, greenish-yellow to pale white mottles occur between dark green areas along the veins. Also, leaves may appear to have a hard semi-glossy surface. If the soil pH continues to drop, mottles may be spread over the entire plant and growth will be stunted. Under extremely acid conditions, the availability of Mn increases and plants take up the nutrient to the extent that it becomes toxic, and plants may eventually die. Plants exhibiting Mn toxicity symptoms usually occur in spots or streaks within the field. Seldom will the entire field be affected. The problem is corrected with the proper use of lime.
1440004	Pythium diseases	Pythium spp.	Damping-off affects tobacco at any stage of growth in the plant bed. The disease first appears as irregular areas of wilted, yellowed, stunted, or dead plants. These symptoms are the result of girdling of the lower stem of the tobacco plants by either Rhizoctonia or Pythium fungi species.Pythium usually affects the young tobacco plant near the soil line. A soft, brown, watery rot girdles the stem, causing the plants to fall over. Plants affected after stems harden may not die but turn yellow due to injury to the stem and root system. Pythium sometimes attacks transplants shortly after they are set in the field, causing a stem rot.
1402078	herbicides (general)		Injury from phenoxy herbicides, such as 2,4-D, causes symptoms that depend on herbicide rate and age of tobacco. Young leaves are puckered and stiff, with very prominent midribs. The tips and margins of the leaves are often serrated. Higher dosages cause strappy leaves with parallel veins and twisted stems. On older plants, and the midrib also bends downward.
1402076	chemicals		Oxamyl injury symptoms are very similar to the physiological disorder of frenching where affected plants develop a large number of leaves and suckers. The leaves are very narrow with prominent midribs. Interveinal chlorosis also occurs.
1440069	hail		Hail damage consists of tears in the leaf web and broken leaves and stalks. Damage may vary greatly among fields or within a given field depending on the severity of the weather conditions. Tobacco damaged later than the normal lay-by time is usually handled as a normal crop. Wind can damage leaves or cause partial or complete blowdown. Early topping reduces late season blowdown. Tobacco blown down after topping should be "stood up" or harvested immediately to prevent loss of leaves. Wind damage following water soaking of the leaves from the underside (wind frazzle) can resemble hail injury but differs in that usually no veins are broken.
1402033	nematodes		Nematodes (microscopic round worms) feed on tobacco roots and can cause stunting, pale color, irregular plant growth, excessive daytime wilting, and poor response to fertilizer. The problem is usually not uniform within a field. Some areas of a field may show severe injury while other areas seem unaffected. Similar symptoms may be caused by other factors such as fertilizer injury, compacted soils, fumigant injury and wireworm damage. A careful examination of the roots and a soil sample for nematode analysis are necessary to diagnose a nematode problem.
1402072	chemicals		Xylene is a chemical carrier present in some emulsifiable concentrate pesticides. When high rates of pesticides containing this chemical are applied under high pressure to young tobacco leaves, injury is very similar to a mild case of 2,4-D injury. The leaves are slightly narrower than normal and may have a glossy appearance, but are not as stiff as those with 2,4-D injury.
1402005	Pythium diseases	Pythium spp.	Soil-borne fungi are the main cause of damping-off. Symptoms first appear on the stem of seedlings as a brown to black rot. The decay extends up the stem and causes the seedlings to collapse. Roots of affected plants may remain healthy. Seedlings die in patches.
1440061	houseburn		Houseburn is also known as pole rot, barn rot, pole sweat, shed burn, vein rot, and stem mold. Symptoms include white mold on midveins, odor of rotting tobacco, and partial decay caused by several species of fungi and bacteria. Freshly harvested tobacco is not highly susceptible, but damage may begin when the cure progresses through the yellowing stage and portions of the leaf begin to die. Injury occurs when microorganisms attack leaves that become moist during periods of high humidity lasting longer than 24 hours. Damage is measured in weight loss and lowered leaf quality and can range from mild to severe. Conditions which favor harvest of immature tobacco and prolonged leaf wetness in the barn will encourage houseburn
1402034	nematodes		Nematodes (microscopic round worms) feed on tobacco roots and can cause stunting, pale color, irregular plant growth, excessive daytime wilting, and poor response to fertilizer. The problem is usually not uniform within a field. Some areas of a field may show severe injury while other areas seem unaffected. Similar symptoms may be caused by other factors such as fertilizer injury, compacted soils, fumigant injury and wireworm damage. A careful examination of the roots and a soil sample for nematode analysis are necessary to diagnose a nematode problem.
1402024	brown spot	Alternaria alternata	This fungal disease appears first on the older leaves as circular, brown spots (1/4 to 1 1/4 inches in diameter) with sharply defined margins. Concentric circles (rings) are often noticeable within the spots. As the leaves approach maturity, a yellowish "halo" of varying width often forms around the lesion. Lesions may merge, forming large areas of dead tissue. During humid weather, sporulation of the fungus may be abundant, giving the lesions a black, dusty appearance. Brown spot is most severe as the plant approaches maturity, and the disease progresses from the lower to the upper leaves. Disease severity depends much on the weather, the overall health of the plant, varietal tolerance, and harvest rate.
1402093	nutrient excess or toxicity (general)		Excessive nitrogen results in large plants and dark green leaves that are larger and thinner than normal. Leaves become thicker as they mature. Leaf maturity is delayed, curability is decreased, and sucker growth is increased.
1440060	branched broomrape	Orobanche ramosa	Plants attacked by broomrape appear sickly, yellowish, and starved, but have few distinguishing symptoms. The presence of small white, yellow, or purple plants with blue flowers growing near the base of the affected tobacco plant is the most diagnostic feature of broomrape. Close examination should reveal that the parasitic plants' roots are attached to the tobacco plant. Stunting symptoms occur because the broomrape plant is taking much of the tobacco plant's food. Affected plants may be located singly or clustered. Several different Orobanche species may parasitize tobacco.
1440019	blue mold	Peronospora tabacina	Blue mold may occur on the plant anytime from seedling to harvest; however, young tissue is more susceptible than old tissue. The first evidence of blue mold in the field usually occurs on the leaves as yellow circular spots about the size of a nickel. The spots soon develop the characteristic bluish, downy fungal growth on the undersides of the leaves which is best seen in the morning when the leaf is wet. If spots develop on leaves that are expanding, a puckering of the leaf occurs. As spots age, they turn from yellow to tan or brown and often tear or drop out. If infection has occurred near or on a leaf vein, a localized systematic infection may occur. The affected vein becomes reddish-brown, and the area around the vein is yellowed and distorted. In newly set transplants, it is possible for the fungus to develop systematically, killing the main bud and resulting in stunting or death of the plant. Splitting the stalk of systematically infected plants reveals a reddish- brown discoloration in the vascular tissue beneath the epidermis. A one-sided systemically infection also occur, resulting in a deformed stalk and lodging of affected plants. During weather favorable for blue mold (cool, cloudy, and wet), the disease can develop rapidly, causing numerous leaf lesions which can result in leaf blighting and severe leaf loss. The disease may develop during hot, humid periods if cool nights exist.
1402073	chemicals		Carbofuran can cause small, irregular, oval-shaped lesions to first appear on the bottom leaves and progress upwards, especially under dry conditions. The white-tan to brown-yellow lesions are first produced on the leaf margins, followed by numerous lesions between the veins on the entire leaf. With high chemical concentrations, the leaf edges may be cupped upwards or curled downwards and the leaves may be narrow or arrow-shaped. Stunted plants and premature flowering may also occur. Recommended rates and proper application methods may produce a mild flecking but rarely the severe symptoms. Other disorders such as weather fleck and other chemicals may produce similar symptoms.
1440080	herbicides (general)		Tobacco is extremely sensitive to picloram and very small amounts from drift, contaminated equipment, or residue in the soil will cause serious injury. The most common symptom is a downward curling of the margins and tips of the leaf. The curl of the tip results in "parrott beak" or hooded appearance. Symptoms appear first on young growing leaves, but due to the persistence of the compound, it will continue to affect the new bud leaves. New leaves may take on a heart-shaped appearance as the midrib is stunted, while the adjoining tissue continues to grow. Higher rates of picloram result in thick, strappy, elongated older leaves and elongated or aborted bud leaves. Young leaves may also have a wide thick midrib with little or no adjoining leaf tissue. Picloram residues may persist in the soil and cause damage to tobacco for periods of three or more years after application.
1440134	Braconid wasp	Cotesia congregata	The braconid wasp is an important parasite of the tobacco hornworm. The larval stage is a small, white legless grub that develops inside the hornworm. Parasitized hornworms are easily recognized after the wasp larvae spin their white football-shaped cocoons. When the parasite becomes an adult, it leaves through an opening in the end of the cocoon and searches for other hornworms. By late summer 90% or more of the hornworm found on tobacco may be parasitized. Hornworms with cocoons may live for several days but do not feed. Insecticides should not be applied if parasitized hornworms are abundant in the field.
1440121	tobacco thrips	Frankliniella fusca	Tobacco thrips may cause damage to tobacco, especially during dry years. These slender yellow-to-brown insects are about 1/25 inch long. Adults have four very narrow, featherlike wings. Adults and nymphs suck sap from the leaves producing gray to silver feeding marks primarily along the veins of the lower leaves. The leaves also become peppered with minute black spots. The underside of midribs may be damaged. Heavy infestations cause the foliage to turn yellow, as seen here.
1440135	Braconid wasp	Cotesia congregata	The braconid wasp an important parasite of the tobacco hornworm. The larval stage is a small, white legless grub that develops inside the hornworm. Parasitized hornworms are easily recognized after the wasp larvae spin their white football- shaped cocoons. When the parasite becomes an adult, it leaves through an opening in the end of the cocoon and searches for other hornworms. By late summer 90% or more of the hornworm found on tobacco may be parasitized. Hornworms with cocoons may live for several days but do not feed. Insecticides should not be applied if parasitized hornworms are abundant in the field.
1440136	paper wasps	Polistes spp.	Paper wasps (Polistes spp. and others) may be seen searching leaves for food. These wasps attack soft bodied insects, such as hornworms, and use them up to feed larval wasps being raised in their nests. These beneficial insects play a role in the natural control of several tobacco pests. Most people recognize these beneficials as the familiar "stinging" wasps which build paper nests or combs under the eaves of buildings and in dense vegetation.
1440139	genetic abnormalities		Genetically abnormall tobacco plants, while usually of little or no economic importance, may be confused with infectious disease or chemical injuries. These abnormalities may be called monstosities, malformations, enations, anamolies, throwbacks, kickbacks, or runouts. It is unusual to find more than one of these abnormal plants in a field. Most fields contain none. Chimeras or variegated tobacco plants have irregular patches on the leaves that vary in color from creamy-white to yellow-green and give the plant a marbled or mottled appearance. Most variegated plants attain normal size, bloom normally, and produce seed. Sometimes abnormally shaped leaves appear on the affected plant. Patterns may be seen in the cured leaves from variegated plants. Another example of genetic abnormality is ruffles. Leaf margins roll downward, and leaves curve downward. Petioles may be elongated. The leaf blade margin may form pouches or folds upon itself, especially along veins on the underside of the leaf.
1440140	genetic abnormalities		Genetically abnormall tobacco plants, while usually of little or no economic importance, may be confused with infectious disease or chemical injuries. These abnormalities may be called monstosities, malformations, enations, anamolies, throwbacks, kickbacks, or runouts. It is unusual to find more than one of these abnormal plants in a field. Most fields contain none. Chimeras or variegated tobacco plants have irregular patches on the leaves that vary in color from creamy-white to yellow-green and give the plant a marbled or mottled appearance. Most variegated plants attain normal size, bloom normally, and produce seed. Sometimes abnormally shaped leaves appear on the affected plant. Patterns may be seen in the cured leaves from variegated plants. Another example of genetic abnormality is ruffles. Leaf margins roll downward, and leaves curve downward. Petioles may be elongated. The leaf blade margin may form pouches or folds upon itself, especially along veins on the underside of the leaf.
1440115	green peach aphid	Myzus persicae	The green peach aphid is a pale green, soft- bodied insect that is found in clusters on the underside of tobacco leaves. The 1/16-inch long "plant lice" use their sucking mouthparts to remove sap from the plants. Feeding by large numbers of aphids results in thin, lightweight leaves that may ripen prematurely. The sugar rich "honeydew" excreted by aphids builds up on the leaf surface and supports growth of black, sooty mold. The honeydew may cause leaves to stick together and cure to a dark, off-color of poor quality. Green peach aphids may transmit viruses such as tobacco vein mottling virus through their mouthparts. Aphid populations build up after winged females fly into tobacco fields, usually during the middle portion of the growing season. They settle on the leaf to feed and give birth to living young. Large populations can build up in a short period of time due to their short life cycle and the occurrence of several generations during a growing season.
1440014	dodder	Cuscuta spp.	Dodder appears as a conspicuous yellowing thread or vine intertwined among the stems and leaves of tobacco and other plants. The vine is actually a parasitic plant that derives its food from the host plants. This parasite may appear either in the bed or field but is most common in the bed.
1440030	Tobacco Ringspot Virus	Nepovirus TRSV	Tobacco ringspot has the most distinctive symptoms of the virus diseases. The name truly describes the disease because chlorotic or necrotic rings occur in the leaf. A concentric line pattern of chlorotic and necrotic tissue, often forming an "oak leaf" pattern, is very common. The symptoms occasionally are confirmed to one side of the plant. The disease appears early in the season, usually with initial growth after transplanting. Most infected plants recover as new symptomless leaves develop. The virus is transmitted by nematodes. In the field, infected plants may appear alone or clustered. Ringspot may occur in the plant bed.
1402142	Braconid wasp	Cotesia congregata	This important parasitic wasp is a major factor in limiting hornworm numbers and damage, particularly late in the season. The tiny black wasp lays eggs in hornworms. Parasitized hornworms may be recognized by their shortened stubby horns. When these worms are broken open, the tiny, white parasitic larvae can be seen. When they complete their development, the parasites spin white, egg-shaped cocoons on the hornworm’s back. Parasitized hornworms damage tobacco much less and usually remain on the plant for a shorter time than normal hornworms.
1402143	Tachinid flies		Tachinid flies (several species including Winthemia spp. and Archytas marmoratus (Townsend): These flies are hairy and resemble house flies, but some species are slightly larger. The tip of the abdomen may be red. Most lay large eggs on the body of budworms and hornworms. Winthemia manducae Sabrosky & DeLoach is often seen near last stage hornworm larvae. Eggs of this species hatch, and the maggots bore into the hornworm. The hornworm is killed while in the soil during the pupal stage, before it can transform into an adult and initiate a new generation.
1402132	paper wasps	Polistes spp.	Several species of paper wasps search out and kill small hornworms and other tobacco pests. The wasps roll parts of the worms into balls, fly them to their nest, and feed them to their young. Research in the early 1960’s showed the provision of nesting sites near tobacco fields reduced numbers of hornworms and leaf loss. Most people recognize these beneficials as the familiar "stinging" wasps which build paper nests or combs under the eaves of buildings and in dense vegetation.
1402129	grasshoppers		Grasshoppers [various species including the differential grasshopper, Melanoplus differentialis (Thomas) and southern red-legged grasshopper are ¾ to 1 inch long. They are greenish-gray to olive-green or reddish-brown with a yellowish underside. The hind tibiae are red with black spines. The differential grasshopper is 1½ to 2-inches long with a shiny, brownish-yellow color and black V-shaped marks on the outer face of the yellow femur. Immatures (nymphs) are similar but lack fully developed wings. Grasshoppers damage tobacco by chewing ragged holes in the leaves. Most species prefer other plants but will eat tobacco if their food supply is inadequate. Grasshoppers often migrate into tobacco fields from hay fields, pastures, and old fields, especially when populations are high during droughts and following hay mowing or other habitat modifications.
1402117	tobacco aphid	Myzus nicotianae	Tobacco aphid [Myzus nicotianae (Blackman)]: Several species of aphids or plant lice feed on tobacco, but only the tobacco aphid commonly builds up large colonies. Winged aphids fly to plants in the bed or field and being producing wingless young (nymphs). Wingless, aphids are softbodied, pink to red, pale green to yellow-green, pear-shaped, and only about 1/16 inch long when full grown. Most aphids are wingless even as adults, but darker, winged forms may also be produced. Aphids have beak-like mouthparts through which they suck plant juices. In addition, they produce a sticky waste product, honeydew, on which sooty mold develop. As a result of these factors, both yield and quality may be reduced. (This and other species of aphids may also transmit certain virus diseases.) Infestations are characterized by the presence of aphids (mostly on the underside of upper leaves), shiny or greasy honeydew deposits on the upper surface of leaves, and sooty mold. In recent years, the red (pink) form of the tobacco aphid has become much more prevalent than the green form.

Narrow Results by:

Subject Specific Filters:

Type:

Category: (show all)

Order: (show all)

Image Specific Filters:

Descriptor: (show all)

Image Setting:

Person in Image:

Orientation:

Images taken in United States