| 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. |
| 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. |
| 1402017 |
genetic abnormalities |
|
ruffles |
| 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. |
| 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. |
| 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. |
| 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. |
| 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. |
| 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. |
| 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. |
| 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. |
| 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. |
| 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. |
| 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. |
| 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. |
| 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. |
| 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. |
| 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. |
| 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. |
| 1402004 |
weather fleck |
|
on seedlings is often confused with anthracnose |
| 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. |
| 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. |
| 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. |
| 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. |
| 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. |
| 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. |
| 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. |
| 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. |
| 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. |
| 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. |
| 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. |
| 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. |
| 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. |
| 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 |
| 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. |
| 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. |
| 1440139 |
genetic abnormalities |
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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. |
