Disease Codes
A
A – Anthracnose
Scientific Name: Colletotrichum lagenarium
Type: Fungus
Anthracnose is a world-wide fungal disease that affects the growth of cucumbers, tomatoes, and watermelons. This disease is most common in the southern, mid-Atlantic, and mid-Western parts of the United States. Symptoms include lesions on the leaves and then yellowish circular spots begin appearing on the leaves. On watermelons the spots are irregular and turn dark brown or black. The most striking symptom is circular, black, sunken cankers appear on the fruit. When moisture is present, the black center of the lesion is covered with a gelatinous mass of salmon colored spores. With tomatoes, the disease mainly affects the tomato, but also can infect leaves, stems and roots. Sunken water soaked circular spots appear on the tomatoes. Leaves show symptoms of small circular spots with yellow halos. It can cause significant yield loss and even total crops losses. The diseased tomatoes are usually unmarketable. The infected plants should be removed to avoid further infestation. Increase space between the plants to maximize air flow and drying of the leaves. The disease is favorable when temperatures are 75-82 F and usually occur when moisture and humidity are very high. Plan on using a 3 year crop rotation and avoid planting in the same location, year after year, as the disease can survive in over winter on crop debris. Proper tillage practices may be helpful in managing the disease. Fungicides can help manage the disease. The best option is to use disease resistant varieties.
ALS
ALS – Alternaria Leaf Spot
Scientific Name: Alternaria brassicicola, Alternaria cucumerina, Alternaria dauci
Type: Fungus
Alternaria Leaf Spot, also known Alternaria Leaf Blight, is a world-wide fungal disease that affects the growth of broccoli, Brussels sprouts, cabbage, cantaloupes & melons, carrots, cauliflower, cucumbers, kale, kohlrabi, pumpkins, radishes, rutabaga, squash, tomatoes, turnips, and watermelons. Symptoms may first develop on young plants where leaf spots develop, plants become stunted, and damping off may occur. Greenish-brown lesions appear on the leaves, and turn from dark brown to black spots. The disease may appear on the leaves at any stage and start off as concentric circles and mature to lesions with a bulls eye appearance. The leaves curl, turn yellow, wither, and eventually die off, and heavy infestations may cause complete defoliation. The infected plants should be removed to avoid further infestation. Increase space between the plants to maximize air flow and drying of the leaves. The disease is favorable when temperatures are 75-82 F and usually occur when moisture and humidity are very high. Plan on using a 3 year crop rotation and avoid planting in the same location, year after year, as the disease can survive in the soil for 8 years. Fungicides can help manage the disease. The best option is to use disease resistant varieties.
BCTV
BCTV – Beet Curly Top Virus
Type: Virus - Curtovirus
Beet Curly Top Virus is a disease that affects the growth of peppers and tomatoes. Symptoms include yellowing of leaves, leaves curling upwards, and plants are severely stunted. Infected plants usually do not recover and die or remain stunted without setting peppers, or peppers that develops will ripen prematurely.The virus can cause substantial crop loss. The virus is transmitted by the beet leafhopper. The infected plants should be removed and burned to avoid further infestation. Keep the fields weed free. Placing shade cloth over plants. The best option is to use disease resistant varieties.
BD
BD – Blossom Drop
Type: Physiological Disorder
Blossom Drop affects the growth of eggplants, peppers, and tomatoes. Symptoms include flowers forming then dropping without forming fruit or when small fruit drop. Tomatoes and peppers will drop their blossoms when environmentally stressed, when temperatures are too cold or too hot, the weather is too dry or too wet, and when the soil is too nutrient rich or deficient. Most tomatoes, peppers, and eggplants will drop blossoms when daytime temperatures are above 90 degrees F and/or nighttime temperatures are above 75 degrees F. Blossoms will also drop when night temperatures drop below 55 degrees F.
BER
BER - Blossom End Rot
Type: Physiological Disorder
Blossom End Rot is a physiological disorder that affects tomatoes. As tomatoes begin to ripen, black spots on the bottom of the tomato appear. The tomatoes affected by blossom end rot should be picked and discarded. The cause is a calcium deficiency. The condition is not caused by a lack of calcium in the soil, but because the plant is unable to take up the calcium that is already in the soil because of drought or erratic watering. It is most common when the growing season starts out wet and then becomes very dry when tomatoes are setting. Plants are unable to absorb calcium because the soil is too wet or too dry, there is excessive nitrogen in the soil, roots are damage during cultivation, soil pH is either too high or too low, cold soil, and high levels of salts in the soil. Keep consistent levels of moisture in the soil throughout the growing season. Allow soil to warm before planting. Use mulch, such as Red Tomato Mulch, to minimize evaporation and to help maintain consistent moisture in the soil. Test soil so pH is at 6.5. Use Tomato Rot Stop to prevent calcium deficiency. The best option is to use disease resistant varieties.
BLS
BLS – Bacterial Leaf Spot
Scientific Name: Xanthomonas campestris
Type: Bacterium
Bacterial Leaf Spot is a disease that affects the growth of peppers. It is one of most destructive diseases that affects peppers in the Eastern part of the United States. Symptoms may first develop on older plant leaves. Initially brown spots appear on the leaves. The leaves turn yellow and eventually die off. Heavy infestations may cause complete defoliation and cause sun scald. Scab like spots may develop on peppers and are unmarketable. It can cause significant yield loss and even total crops losses. The infected plants should be removed and burned to avoid further infestation. It is spread by seeds, weeds, by splashing rain, and by gardeners working with wet infected plants. Increase space between the plants to maximize air flow and drying of the leaves. The disease is favorable in areas with hot summers and frequent rainfall. Plan on using a 1 year crop rotation and avoid planting in the same location, year after year, as the disease can survive in the soil and infected plant debris. Proper tillage practices may be helpful in managing the disease. Cover the soil with black plastic mulch or black landscape fabric. Use drip irrigation or soaker hoses and avoid overhead watering. Copper fungicides can help manage the disease. The best option is to use disease-free and disease resistant varieties.
BR
BR - Black Rot
Scientific Name: Xanthomonas campestris
Type: Bacterium
Black Rot is a disease that affects the growth of arugula, broccoli, Brussels sprouts, cabbage, cauliflower, collards, kale, kohlrabi, mustard, radishes, rutabaga, Swiss chard, tomatoes, turnips, and watercress. It survives in warm wet weather and affects cabbage throughout the United States. It is spread from one field to another field by water and wind. The bacteria can infect seeds and young seedlings. Young plants infected will turn yellow, drop lower leaves, and may die. Once the plant is infected there is no rescue treatment since the infection is systemic. Symptoms include the yellowing of the leaves in v-shape or wedge-shaped patches and blackening of the internal vein. Usually only a few of the outer leaves are affected. Since the disease is spread by water, anything that can be done to reduce leaf wetness will help reduce the spread of the disease. Water the plants in the morning, instead of the watering in the afternoon or night, so the leaves have time to dry before sunset. Increase space between the plants to maximize air flow and drying of the leaves. The disease is favorable when temperatures are 75-95 F and rain, heavy fogs, and dew are present. The bacteria does not spread when temperatures are below 50 F or during dry weather. Plan on using a 3 year crop rotation and avoid planting in the same location, year after year, as the disease can survive in the soil for two years. Treating the infected area with fungicides can help manage the disease. The primary source of bacteria of black rot is infested seeds and in infested transplants. The best option is to use disease resistant varieties, disease-free seeds, and disease-free transplants.
BRib
BRib - Brown Rib
Type: Physiological Disorder
Brown Rib is a physiological disorder that affects lettuce. The disease cause dark brown to black streaks on the wrapper leaves first, then the discoloration extends to veins and ribs. The brown streaks along the ribs and veins of the leaves are often followed by soft rot. The cause is not proven, but it is thought to be heat stress and fluctuations of temperatures. Symptoms occur in the fields during warmest periods of the growing season. The best option is to use disease resistant varieties.
BS
BS - Bacterial Speck
Scientific Name: Pseudomonas syringae
Type: Bacterium
Bacterial Speck is a disease that affects the growth of peppers and tomatoes. Symptoms include small brown spots brown in the center surrounded by a yellow ring on the leaves and curling of the leaves. In severe cases, the spots will spread to the tomato. It is caused by infected seeds and is spread by farm equipment, tools, workers, wind, and water. The infected plants should be removed to avoid further infestation. Cool moist conditions contribute to the development of the disease. The disease is favorable when temperatures are 63-75 F and usually occur when moisture and humidity are very high. Plan on using a 3 year crop rotation and avoid planting in the same location, year after year. Increasing space between the plants can help control and prevent the disease, as the disease can be spread from plant to plant in crowded conditions. Keep the fields weed free. Copper fungicides can help manage the disease. The best option is to use disease resistant varieties.
BSP
BSP - Black Speck (Pepper Spot)
Type: Physiological Disorder
Black Speck, also known as Pepper Spot, is a physiological disorder that affects cabbage, especially Chinese Napa Cabbage in the United States and Europe. The disease affects the outer leaves of the cabbage, but often can seen deep in the center of the head. Individual brown and black spots develops on the wrapper leaves, and then spread to the inner leaves. Dark lesions spots appear on the cabbage ribs. It appears as if black pepper was sprinkled on the midrib section of the leaves, hence the name "pepper spot". The cause is unknown, but high rates of fertilizers and fluctuations of temperatures have been reported to increase the susceptibility. Symptoms occur in the fields during growth and during cold storage. The best option is to use disease resistant varieties.
BSR
BSR - Bacterial Soft Rot
Scientific Name: Erwinia carotovora
Type: Bacterium
Bacterial Soft Rot is a disease that affects the growth of arugula, broccoli, Brussels sprouts, cabbage, cauliflower, collards, kale, kohlrabi, mustard, radishes, rutabaga, turnips, and watercress. It may occur in the field, in the garden, in the greenhouse, or
after harvest during transit and storage. The disease enters the plant through cracks or wounds and survives in warm wet weather and affects cabbage throughout the United States. It starts on the leaves, stems, and underground parts as small translucent spots. The plant tissue softens and becomes mushy or watery. The decaying tissue gives off a distinctive odor. The disease is favorable when temperatures are 70-80 F and usually occur when moisture and humidity are very high. The best option is to use disease resistant varieties.
BW
BW - Bacterial Wilt
Scientific Name: Erwinia tracheiphila
Type: Bacterium
Bacterial Wilt is a disease that affects the growth of cantaloupes & melons, cucumbers, eggplants, gourds, pumpkins, squash, and tomatoes. Symptoms include wilting and drying of individual leaves. As the leaves wilt and shrivel, stems may dry out suddenly. Later, wilting spreads to entire branches and vines. Wilting will occur during the middle of the day during periods with high water stress. The vine may recover at night. Eventually, however, the entire vine will wither, collapse, and die. Bacterial wilt is spread from plant to plant through cucumber beetles that feed on cucumbers. The infected plants should be removed to avoid further infestation. Plan on using a 3 year crop rotation and avoid planting in the same location, year after year. Use insecticides like Admire, Platinum, or Sevin in the spring, between April and June, before the cucumber beetles have a chance to lay eggs. The best option is to use disease resistant varieties.
BYMV
BYMV – Bean Yellow Mosaic Virus
Type: Virus - Potyvirus
Bean Yellow Mosaic Virus is a disease that affects the growth of peas. It is primarily found in Northeastern parts of the United States (New York), Europe, and the Middle East. Symptoms include bright yellow to green mosaic, leaf malformation, and leaf mottling, down cupping and wrinkling of leaves. Often bright yellow spots appear on the leaves. There may be severe stunting of the plants, and sometimes death of plants. The virus can cause substantial crop loss. The virus is transmitted by aphids and is not transmitted by seeds. The virus survives for long periods in infected alfalfa and weeds. Mild winter temperatures favor survival of the virus, thus the disease can be greater the following spring. The infected plants should be removed and burned to avoid further infestation. Plan on using a 3 year crop rotation and avoid planting in the same location, year after year. Insecticides for aphids can control the disease. The best option is to use disease resistant varieties.
Ccu
Ccu – Scab
Scientific Name: Cladosporium cucumerinum
Type: Fungus
Scab is a world-wide fungal disease that affects the growth of cantaloupes & melons, cucumbers, gourds, pumpkins, squash, and watermelons. Symptoms include pale green spots appear on the leaves which turn to gray spots and may have a yellow halo surrounding the lesion. The leaves become wrinkled and have ragged holes. The dead leaves crack and eventually fall off the plant. Cucumbers, pumpkins, and squash have sunken spots covered with greenish black velvety fungus. The fungus spores are spread by wind, insects, tools, and workers. The scab fungus overwinters on the seed, in crop debris, and in soil. The infected plants and vegetables should be removed, burned, or tilled in to avoid further infestation. The disease is favorable when temperatures are 59 - 77 F and usually occur when moisture and humidity are very high. Plan on using a 2 year crop rotation and avoid planting in the same location, year after year, as the disease can survive in over winter on crop debris. Proper tillage practices may be helpful in managing the disease. Control weeds, by tilling. Fungicides can help manage the disease. Use drip irrigation instead of overhead sprinklers if possible. Keep the day temperature in the 80's and have proper air circulation in greenhouses. The best option is to use disease resistant varieties.
CGMMV
CGMMV – Cucumber Green Mottle Mosaic Virus
Type: Virus - Tobamovirus
Cucumber Green Mottle Mosaic Virus is a world-wide virus disease that affects the growth of cucumbers. Symptoms include green and light green spots and yellow-green spots on young leaves and reduced growth rate and yields. Symptoms include vein clearing and crumpling on young leaves while mature leaves become bleached and chlorotic. Cucumbers from infected plants may be severely spotted and distorted. The virus can cause substantial crop loss. It is spread through root to root contact. The virus is not known to be transmitted by insects. The virus survives for long periods in infected crop debris, seeds, and weeds. The virus can be spread by infected seeds. Infection of the plants in the field can start when the roots encounter infected debris buried in the soil. The infected plants should be removed and burned to avoid further infestation. Plan on using a 3 year crop rotation and avoid planting in the same location, year after year. Keep the fields weed free. The best option is to use disease resistant varieties.
CLS
CLS – Cercospora Leaf Spot
Scientific Name: Cercospora asparagi, Cercospora beticola
Type: Fungus
Cercospora Leaf Spot is a world-wide fungal disease that affects the growth of asparagus, beets, carrots, corn, eggplants, peppers, soybeans, and tomatoes. It is the most destructive foliage disease of beets in Colorado, Nebraska, and Wyoming. Leaf spots occur on leaves. Symptoms include lesions of round or angular brown spots with green, brown, gray, or white centers. The leaves turn yellow, wither, and eventually die off and the whole plant becomes defoliated. The infected plants should be removed to avoid further infestation. The disease is favorable when temperatures are 55-65 F and usually occur between June and August when moisture and humidity are very high. Fungicides can help manage the disease. The best option is to use disease resistant varieties.
CMV
CMV – Cucumber Mosaic Virus
Type: Virus - Potyvirus
Cucumber Mosaic Virus is a world-wide virus disease that affects the growth of cantaloupes & melons, cucumbers, eggplants, gourds, peppers, pumpkins, spinach, squash, tomatoes, and watermelons. Symptoms include stunted or dwarfed plants, mottling, yellowing, distortion, and wrinkling of the leaves with the edges curling downward, and reduced growth rate and yields. The symptoms on leaves known as "shoestring" effect causes young leaves to appear narrow. The leaves will die and fall off, leaving part or most of the plant bare. The virus causes cucumbers to turn pale and gray, become bumpy and oddly shaped, and have a bitter taste. The virus causes peppers to have severe leaf damage with mosaic and necrotic rings. The peppers may have rings and spots. Tomato plants are usually stunted and have poorly shaped leaves and can cause partial or total crop loss. Plants infected with the virus have little or no marketable fruit. The virus can reduce yields and fruit quality. It is spread by aphids, seeds, and weeds. The virus overwinters in many perennial weeds. The infected plants should be removed to avoid further infestation. This virus cannot live in extremely dry conditions. The disease is favorable when temperatures are 79-89 F when aphid infestation is great. Symptoms usually begin to show in June. Plan on using a 3 year crop rotation and avoid planting in the same location, year after year. Keep the fields weed free as infected perennials can harbor the virus. Proper tillage practices may be helpful in managing the disease. Insecticides for aphids are of limited value to control the disease. Spraying the tomato plants with mineral oil can delay the aphids from spreading the virus.The best option is to use disease resistant varieties.
CR
CR – Clubroot
Scientific Name: Plasmodiophora brassicae
Type: Fungus
Clubroot is a world-wide fungal soil-borne disease that affects the growth of cabbage, cauliflower, broccoli, Brussels sprouts, kohlrabi, radishes, rutabaga, tomatoes, and turnips. This disease can cause severe crop yields and total crop loss. The fungus infects the plant through root hairs or wounds. Symptoms include wilting and yellowing of leaves. Young plants are stunted and may die. The roots are usually swollen and distorted (clubbed). The disease is spread by farm equipment, wind, and water. The infected plants should be removed and burned to avoid further infestation. The disease is favorable when temperatures are 54-81 F and usually occur when soil is moist. The disease is primarily associated with acid soils. Plan on using a 7 year crop rotation and avoid planting in the same location, year after year, as the disease can survive in the soil up to 20 years. Use proper weed control techniques. Proper tillage practices may be helpful in managing the disease. It is essential that hydrated lime be added each year to the soil unless the soil pH exceeds 7.5. Thoroughly clean equipment after working in a field. Plant crops in well drained soil. The best option is to use disease resistant varieties.
CVYV
CVYV – Cucumber Vein Yellowing Virus
Type: Virus - Ipomovirus
Cucumber Vein Yellowing Virus is a world-wide virus disease that affects the growth of cucumbers and watermelons. Symptoms include vein yellowing and vein clearing of the leaves and stunting of the plants. Light to dark green mosaic is observed on cucumbers. Watermelon splitting has been observed. The virus can reduce yields. It is spread by the whitefly. The virus overwinters in many perennial weeds. The infected plants should be removed to avoid further infestation. Plan on using a 3 year crop rotation and avoid planting in the same location, year after year. Keep the fields weed free as infected perennials can harbor the virus. Proper tillage practices may be helpful in managing the disease. Insecticides for whiteflies may help control the disease. The best option is to use disease resistant varieties.
DM
DM – Downy Mildew
Scientific Name: Peronospora farinosa, Peronospora parasitica, Pseudoperonospora cubensis
Type: Fungus
Downy mildew is a fungal disease that affects the growth of beets, broccoli, cantaloupes & melons, cauliflower, cucumbers, spinach, Swiss chard, and watermelons. Downy Mildew is most serious for cucumbers, which can drop dead in a week and stop producing any fruit to harvest. The disease affects both seedlings and mature plants.The infected leaves are retarded in growth, turn yellow then brown, and turn downward. A white to gray color mold appears on the underside of the leaves. The leaves will wilt and eventually die. The disease can spread rapidly under favorable conditions and infect the entire field. The infected plants should be removed and burned to avoid further infestation. The disease is favorable when temperatures are 58-72 F and usually occur in early spring and autumn in cooler weather when moisture and humidity are very high. Fungicides can help manage the disease. Good air circulation and increasing space between the plants can help control and prevent the disease, so use wide plant spacing to promote drying of the leaves. The best option is to use disease resistant varieties.
EB
EB – Early Blight
Scientific Name: Alternaria solani
Type: Fungus
Early Blight is a soil-borne disease that affects the growth of tomatoes. This disease is most common in North America. The symptoms include collar rust on the stems, circular dark spots appear on the leaves, rings surround the spots with a yellow halo, and tomatoes crack at the stem. The leaves may die and fall off the plant resulting in extensive defoliation, exposing the tomatoes to sun scald. Black spots may appear on the tomatoes. The disease can cause substantial yield loss and total crop loss. It is spread by wind and water. The infected plants should be removed and burned to avoid further infestation. The virus can live in plant debris and in the soil. The disease is favorable when temperatures are 82-86 F and usually occur when moisture and humidity are very high. Plan on using a 2 to 3 year crop rotation and avoid planting in the same location, year after year, and can survive in the soil for 1 year. Fungicides can help manage the disease. Stake plants to improve air circulation. Use drip irrigation to keep foliage dry and avoid overhead irrigation. The best option is to use virus-free seeds and disease resistant varieties
F
F – Fusarium Wilt (Race 1)
Scientific Name: Fusarium oxysporum
Type: Fungus
Fusarium Wilt, Race 1, is a fungal disease that affects the growth of tomatoes. It is one of the most devastating of all soil-borne diseases. Race 1 is the most widely found throughout the United States, especially in warm regions of the country. It attacks the roots of the plants and moves up the stems. Symptoms include yellowing and browning of the older bottom leaves, stunting, and wilting. Often the entire plant will die. Usually little or no fruit develops. The infected plants will produce inferior and unmarketable tomatoes. It can cause significant yield loss and even total crops losses. If you stick with Fusarium Wilt Resistant tomato varieties you don’t have to worry. Many of the older heirlooms don’t have any resistance to the disease, so if you grow these then you should keep an eye out for it. The infected plants should be removed and burned to avoid further infestation. Plan on using a 5 to 7 year crop rotation and avoid planting in the same location, year after year, as the disease can survive in the soil up to 10 years. The best option is to use disease resistant varieties.
FF
FF – Fusarium Wilt (Race 2)
Scientific Name: Fusarium oxysporum
Type: Fungus
Fusarium Wilt, Race 2, is a world-wide fungal disease that affects the growth of tomatoes. It is one of the most devastating of all soil-borne diseases. Race 2 is found in Arkansas, Florida, New Jersey, and Ohio in the United States. It attacks the roots of the plants and moves up the stems. Symptoms include yellowing and browning of the older bottom leaves, stunting, and wilting. Often the entire plant will die. Usually little or no fruit develops. The infected plants will produce inferior and unmarketable tomatoes. It can cause significant yield loss and even total crops losses. If you stick with Fusarium Wilt Resistant tomato varieties you don’t have to worry. Many of the older heirlooms don’t have any resistance to the disease, so if you grow these then you should keep an eye out for it. The infected plants should be removed and burned to avoid further infestation. Plan on using a 5 to 7 year crop rotation and avoid planting in the same location, year after year, as the disease can survive in the soil up to 10 years. The best option is to use disease resistant varieties.
FFF
FFF – Fusarium Wilt (Race 3)
Scientific Name: Fusarium oxysporum
Type: Fungus
Fusarium Wilt, Race 3, is a world-wide fungal disease that affects the growth of tomatoes. It is one of the most devastating of all soil-borne diseases. Race 3 is found in California, Florida, North Carolina, and South Carolina in the United States. It attacks the roots of the plants and moves up the stems. Symptoms include yellowing and browning of the older bottom leaves, stunting, and wilting. Often the entire plant will die. Usually little or no fruit develops. The infected plants will produce inferior and unmarketable tomatoes. It can cause significant yield loss and even total crops losses. If you stick with Fusarium Wilt Resistant tomato varieties you don’t have to worry. Many of the older heirlooms don’t have any resistance to the disease, so if you grow these then you should keep an eye out for it. The infected plants should be removed and burned to avoid further infestation. Plan on using a 5 to 7 year crop rotation and avoid planting in the same location, year after year, as the disease can survive in the soil up to 10 years. The best option is to use disease resistant varieties.
FBR
FBR - Fusarium Basal Rot
Scientific Name: Fusarium oxysporum f. Sp. Cepea
Type: Fungus
Fusarium Basal Rot is a world-wide soil borne disease that affects the growth of chives, garlic, leeks, onions, and shallots. The disease can start at any stage of the growth of the onion, but usually begins during bulb formation. Symptoms of wilting of the leaves may occur and the leaves turn a yellow color and start to die off. Onions infected with Fusarium Basal Rot often show a red-brown color on the stems and roots, then progressing to a dark brown color. White fungus will develop at the base of the plant and the plant will eventually die. The surviving plants will have bulbs that become soft and non-desirable. The disease is not often noticed until onions are harvested when moldy roots are exposed. Protect the onion plants from insect, especially root maggots, to avoid the spreading of the disease to other plants and further damage to bulb. The disease tends to occur when planted in poorly drained soil, so try to improve soil conditions and utilize raised beds techniques. The disease is also favorable when temperatures are 82-90 F, and usually occur between mid to late summer. Plan on using a 4 year crop rotation and avoid planting onions in the same location, year after year as the disease can survive in the soil for a long time. The best option is to use disease resistant varieties and/or use a root fungicide for soil based diseases.
FCRR
FCRR– Fusarium Crown & Root Rot
Scientific Name: Fusarium oxysporum f. sp. asparagi, Fusarium proliferatum, and Fusarium moniliforme
Type: Fungus
Fusarium Crown & Root Rot is a devastating world-wide soil borne disease that affects the growth of asparagus and tomatoes. The disease affects the roots. Symptoms include wilting, stunting, yellowing, and dry rot of the crowns. Often the crown turns a brown color when it is infected with the disease and then rapidly dies off. Once the plant is infected, it is extremely difficult to manage the disease once the fungus is established in the field. Plan on using a 5 year crop rotation and avoid planting asparagus in the same location, year after year as the disease can survive in the soil for a long time. The best option is to use disease resistant varieties.
FY
FY - Fusarium Yellows
Scientific Name: Fusarium oxysporum f. sp. conglutinans
Type: Fungus
Fusarium Yellows is a soil borne disease that affects the growth of broccoli, Brussels sprouts, cabbage, cauliflower, collards, kale, kohlrabi, mustard, radishes, rutabaga, turnips, and watercress. It is a warm weather disease affecting cabbage throughout the United States. Cabbage and radish crops can be completely destroyed when the soil is infected with the disease. Symptoms include the curling of the leaves and the leaves turning a dull green to a yellowish-green color within a month after transplanting into the field. Young plants may be stunted, turn yellow, and die rapidly in warm weather. The leaves will turn yellow, then brown, wither, and eventually drop off the plant. The infected plants usually die within 2 weeks, other may die slowly. The surviving infected plants will have poor heads of cabbages that are non-desirable. The disease is sometimes confused with black rot, where the leaf veins turn black, rather than turning brown. The disease is favorable when temperatures are 80-85 F. Since the disease can survive in the soil for a long time, crop rotation, fungicide treatment, and destruction of crops, will have little impact once the soil is infected. The only option is to use disease resistant varieties.
FW
FW – Fusarium Wilt
Scientific Name: Fusarium oxysporum
Type: Fungus
Fusarium Wilt is a fungal disease that affects the growth of cantaloupes & melons, cauliflower, eggplants, peas, peppers, squash, tomatoes, and watermelons. It is one of the most devastating of all soil-borne diseases. It attacks the roots of the plants and moves up the stems. Symptoms include stunting and wilting. Plants don’t always die, but it slows growth and reduces yields. Infected seedlings will damping off, wilt, and die. If you stick with fusarium wilt resistant tomato varieties you don’t have to worry. Many of the older heirlooms don’t have any resistance to the disease, so if you grow these then you should keep an eye out for it. The infected plants should be removed to avoid further infestation. Plan on using a 3 year crop rotation and avoid planting in the same location, year after year, as the disease can survive in the soil for 7 years. The best option is to use disease resistant varieties.
GW
GW – Gray Wall
Type: Physiological Disorder
Gray Wall, also referred to as Blotchy Ripening, is a physiological condition associated with environmental factors that affects the growth of tomatoes. Symptoms include black to dark brown tissue in the walls of the tomatoes. Tomatoes look splotchy and mottled resulting in uneven ripening. The grayish splotches on tomato surfaces may even collapse inward – thus the condition’s name. The inside of an affected tomato may also have grayish, yellowish, brownish, or greenish patches internal whitening and yellow shoulders. It does not affect the stems and leaves of the plant. It can cause substantial yield loss and total crop loss, if not controlled. It is caused by extreme heat, high humidity, temperature fluctuations, clouds during hot weather, excessive nitrogen, lower levels of potassium, and high soil moisture. Make sure plants aren't heavily shaded, using a good irrigation program, and that the soil is not compacted around the plants. Test the soil each year for nitrogen and potassium. Grow varieties that are resistant to TMV. The best option is to use disease resistant varieties
LB
LB – Late Blight
Scientific Name: Phytophthora infestans
Type: Oomycete
Late Blight is a fungal disease that affects the growth of potatoes and tomatoes. Symptoms include large dark brown blotches with a green gray edge on the leaves resulting in large sections of dry brown foliage. Stems become dark brown. Dark brown circular spots cover most of the tomato. The entire field turns brown and wilted as if it was hit by frost and die.It can cause significant yield loss and even total crops losses. The diseased tomatoes are usually unmarketable. Late blight was responsible for the Irish potato famine of the late 1840s. The air-borne disease can destroy an entire field in a short period of time. The infected plants should be removed and burned to avoid further infestation. If you stick with Late Blight resistant tomato varieties you don’t have to worry. The disease is favorable when temperatures are 60-70 F and usually occur when moisture and humidity are very high. Plan on using a 3 year crop rotation and avoid planting in the same location, year after year, as the disease can survive in the soil for 7 years. Fungicides are available for management of late blight on tomatoes. The best option is to use disease resistant varieties.
LD
LD – Lettuce Drop
Scientific Name: Sclerotinia sclerotiorum and Sclerotinia minor
Type: Fungus
Lettuce Drop is a world-wide fungal disease that affects the growth of lettuce. The stems and leaves come in contact with the infected soil. Symptoms include wilting of the lower leaves and then leaves drop to the soil. The crown will develop a brown, soft, watery decay followed by the development of a snowy-white mycelium that eventually destroys the tissue. The entire plant will wilt and then collapse, making it unharvestable. The infected plants should be removed and burned to avoid further infestation. Increase space between the plants to maximize air flow and drying of the leaves. The disease is favorable when temperatures are cool, conditions are moist, and soil is wet. Plan on using a 3 year crop rotation and avoid planting in the same location, year after year, as the disease can survive in the soil for 2 to 3 years. Deep tilling may be helpful in managing the disease. Drip irrigation below the soil surface. Assure good drainage with beds as high as possible. Fungicides can help manage the disease. The best option is to use disease resistant varieties.
LM
LM – Leaf Mold
Scientific Name: Passalora fulva
Type: Fungus
Leaf Mold is a soil-borne disease that affects the growth of tomatoes. Often the only part of the plant infected. Symptoms include greenish-yellow spots on the upper sides of leaves, then turn brown. Infected leaves will wilt and die. Infected blossoms turn black and fall off. In severe cases, black areas on the stem end of the tomato will develop. The disease can cause substantial yield loss and total crop loss. It is spread by farm equipment, tools, workers, wind, and water. The infected plants should be removed and burned to avoid further infestation. The virus can live in plant debris and in the soil. The disease is favorable when temperatures are 71-75 F and usually occur when moisture and humidity are very high. Plan on using a 2 to 3 year crop rotation and avoid planting in the same location, year after year, and can survive in the soil for 1 year. Stake plants and increase space between the plants for improved air circulation. Use drip irrigation to keep foliage dry and avoid overhead irrigation. Fungicides can help manage the disease. The best option is to use virus-free seeds and disease resistant varieties
LMV
LMV – Lettuce Mosaic Virus
Type: Virus - Potyvirus
Lettuce Mosaic Virus is a world-wide seed-borne disease that affects the growth of endive, lettuce, and spinach. Symptoms include stunted or dwarfed plants, show a mosaic or mottling pattern on leaves, and plants rarely grow to full size. Head lettuce may fail to form heads and the wrapper leaves often will curve back away from the head. Outer leaves will be yellow, twisted, and deformed. Yellow or brown blotches may appear on the leaves. Severe infection can lead to the death of the plant. The disease can cause substantial yield loss and total crop loss. It is a seed-borne disease and is spread by aphids. The virus can live in weeds, so use weed management techniques. Plan on using a 3 year crop rotation and avoid planting in the same location, year after year. Keep the fields weed free. Proper tillage practices may be helpful in managing the disease. Insecticides for aphids are of limited value to control the disease. The best option is to use virus-free seeds and disease resistant varieties.
MDMV
MDMV – Maize Dwarf Mosaic Virus
Type: Virus - Potyvirus
Maize Dwarf Mosaic Virus is a world-wide virus disease that affects the growth of corn. Symptoms include yellowing of the leaves, then red streaks or blotches appear later in a mottle or a mosaic pattern. Plants show stunting after the infection is established. Ear formation and development may slow, which can cause substantial yield loss. The disease is spread by aphids. The disease is favorable when night temperatures are consistently around 60 F. Plan on using a 3 year crop rotation and avoid planting in the same location, year after year. Insecticides for aphids are of limited value to control the disease. Controlling Johnson grass with herbicides may be beneficial in the management of the disease. The best option is to use disease resistant varieties.
N
N – Root-Knot Nematode
Scientific Name: Meloidogyne spp.
Type: Parasites
Nematodes are soil dwelling parasites that feed on plant roots and affect cucumbers, okra, peppers, squash, and tomatoes. Symptoms include yellowing of the leaves, wilting, and stunting of the plant. The plant will have galled and decayed roots. Nematodes are most active when soil temperatures are 85 - 95 F and usually occur when the soil is moisture. Plan on using a 3 year crop rotation and avoid planting in the same location, year after year. Nematodes are most active in warm soils and they need water to thrive so take advantage of summer’s heat to wither them away. Withhold water from nematode infested areas of the garden and turn or till the soil every 7-10 days during the summer to expose nematodes to the drying effects of the sun. Proper tillage practices may be helpful in managing the disease. Certain types of marigolds work by excreting a substance that is damaging to nematodes as well as trapping them in their roots and preventing reproduction. Elbon rye is an effective nematode control that can be planted as a cool season cover crop that is turned under in early spring. The use of soil fumigants like Vapam has been helpful and a fungicide called Actinovate can also be helpful in managing the lowering of the nematode population. Using transparent plastic mulches for 4 to 6 weeks have been shown to kill nematodes. The best option is to use disease resistant varieties.
NCLB
NCLB – Northern Corn Leaf Blight
Scientific Name: Exserohilum turcicum
Type: Fungus
Northern Corn Leaf Blight is a fungal disease that affects the growth of corn. Northern corn leaf blight occurs commonly in the Midwestern regions of the United States. Symptoms are cigar-shaped or elliptical shaped gray-green lesions on the leaves that range from 1 to 7 inches long. Lesions begin on the lower leaves and then spread to upper leaves. Severe symptoms can progress rapidly, resulting in blighted leaves. Lesions can also be found on the husk of ears or the leaf sheaths. It can cause significant yield loss in corn. Losses are greater and more severe when plants are infected at the early stage of growth. The disease will spread by rain or wind. The disease is favorable when temperatures are 64-81 F and usually occur when moisture and humidity are very high. Plants usually become infected when water is present on the leaf surface for 6 to 18 hours. Plan on using a 3 year crop rotation and avoid planting in the same location, year after year, as the disease can survive in over winter on corn leaf debris. Proper tillage practices may be helpful in managing the disease. Fungicides can help manage the disease. The best option is to use hybrid disease resistant varieties.
OYDV
OYDV - Onion Yellow Dwarf
Type: Virus - Potyviridae
Yellow Dwarf is a virus disease that affects the growth of garlic, onions, and shallots. It was first discovered in Pleasant Valley, Iowa adjacent to the Mississippi River in June of 1927. Although the virus is not spread to the seeds, seeds from infected plants are of poor quality. Symptoms of yellow dwarf include yellow streaks and complete yellowing at the base of the true first leaves. The leaves are usually crinkled, twisted, and flattened and usually fall over. The plants will be wilted and dwarf and bulbs are usually underdeveloped and do not reach full size. The virus is spread by aphids. Controlling aphids does not prevent the disease, as they quickly transmit the virus as they move through the field and infect the crop. Use onion seeds rather than onion sets. The best option is to use disease resistant varieties.
PEMV
PEMV – Pea Enation Mosaic Virus
Type: Virus - Enamovirus
Pea Enation Mosaic Virus is a disease that affects the growth of peas. Symptoms include bright yellow mosaic on the leaves. downward leaf rolling, blistering, severe stunting of the plants. Pods are distorted, split open, shows enations and contain few, if any, seeds. The virus can cause substantial crop loss and complete crop loss. The virus is transmitted by aphids and is not transmitted by seeds. The virus survives for long periods in infected weeds. Mild winter temperatures favor survival of the virus, thus the disease can be greater the following spring. The infected plants should be removed and burned to avoid further infestation. Plan on using a 3 year crop rotation and avoid planting in the same location, year after year. Insecticides for aphids can control the disease. Predators, like lady bugs, can be used to prevent an outbreak of the virus. The best option is to use disease resistant varieties.
PLRV
PLRV – Pea Leaf Roll Virus
Type: Virus - Luteovirus
Pea Leaf Roll Virus, also known as Bean Leaf Roll Virus, is a disease that affects the growth of peas. It is primarily found in Northwestern parts of the United States (Idaho, Oregon, and Washington) and Europe (France, Germany, and Netherlands). In 1980, a severe epidemic of the disease caused severe crop losses in southern Idaho, where 80% of the peas are produced in the United States. Symptoms include yellowing and mottling of leaves, sometimes downward leaf rolling, severe stunting of the plants, and the death of plants. The virus can cause substantial crop loss and complete crop loss. The virus is transmitted by aphids and is not transmitted by seeds. The virus survives for long periods in infected alfalfa. Mild winter temperatures favor survival of the virus, thus the disease can be greater the following spring. The infected plants should be removed and burned to avoid further infestation. Plan on using a 3 year crop rotation and avoid planting in the same location, year after year. Insecticides for aphids can control the disease. The best option is to use disease resistant varieties.
PM
PM – Powdery Mildew
Scientific Name: Erysiphe betae
Type: Fungus
Powdery mildew is a fungal disease that affects the growth of beets, cantaloupes & melons, cucumbers, peas, squash, Swiss chard, and tomatoes. The fungal disease may cause poor growth of the fruits in cucumbers if the infection is severe. The leaves of the cucumber begin to wither and then fall off prematurely. The disease usually affects older leaves. The leaves tend to turn a light green or a yellow green when infected. A powdery white or light gray color mold appears on the underside of the leaves. An odor similar to that of a musty basement is noticeable in fields with severe powdery mildew. The disease can spread rapidly under favorable conditions and infect the entire leaves within a week. The disease is favorable with long periods of dry weather, warm days, and cool nights, and fluctuations of day/night temperatures. The most favorable temperatures are 54-81 F and usually occur in early spring and autumn when moisture and humidity are very high. The disease can spread rapidly and can infect a field within 5 days. Fungicides for powdery mildew can help manage the disease. Good air circulation and increasing space between the plants can help control and prevent the disease. The best option is to use disease resistant varieties.
PMV
PMV – Pepper Mottle Virus
Type: Virus - Potyvirus
Pepper Mottle Virus is a disease that affects the growth of peppers. The disease is found in tropical and sub-tropical regions, including Florida. Symptoms include crinkled leaves, light and dark patches on the foliage that give the plant a mottled appearance, and dark green vein banding. The peppers are usually small and deformed. There may be severe stunting of the plants. The virus can cause substantial crop loss. The infected plants should be removed and burned to avoid further infestation. The virus is transmitted by aphids and is not transmitted by seeds. It is spread by aphids to nearby weeds, which act as future reservoirs for the virus, so it is important to keep the fields weed free. Insecticides for aphids can control the disease. The best option is to use disease resistant varieties.
PR
PR - Pink Rot
Scientific Name: Phoma terrestris
Type: Fungus
Pink Rot is a devastating soil borne disease that affects the growth of onions and can occasionally affect corn, peppers, spinach, and soybeans. The disease started in North Carolina and the mid-Atlantic region and continues to spread to other areas. The disease affects the roots, where they become shriveled and deteriorate, and then may disintegrate. Symptoms of wilting of the leaves may occur and the leaves turn a pale green and start to die off. Onions infected with Pink Root often show a light pink color, then becoming a darker pink color, and progressing to a purple-brown color. The plant is rarely killed by the disease, but the bulbs never matures fully. The surviving plants are stunted and the bulb size is reduced and becomes soft and non-desirable. Cold weather, drought conditions, insect spreading the disease, nutrient deficiencies, and other diseases, can cause stress to the plant which can increase the severity of the disease. Plan on using a 6 year crop rotation and avoid planting onions in the same location, year after year as the disease can survive in the soil for a long time. The best option is to use disease resistant varieties and/or use a root fungicide for soil based diseases.
PRSV
PRSV – Papaya Ringspot Virus
Type: Virus - Potyvirus
Papaya Ringspot Virus is a virus disease that affects the growth of cantaloupes & melons, cucumbers, pumpkins, and squash. Papaya ringspot virus is primarily a problem in the southern and western regions of the United States. Symptoms include yellowing and vein-clearing of young leaves, yellow mottling of the leaves, distinctive ringspot patterns on the fruit, and fruit quality, particularly flavor, is adversely affected. The infected plants should be removed to avoid further infestation. It is only spread by aphids. There is no cure for papaya ringspot disease. Insecticides for aphids are of limited value to control the disease. The best option is to use disease resistant varieties.
PSV
PSV – Pea Streak Virus
Type: Virus - Carlavirus
Pea Streak Virus is a disease that affects the growth of peas. It is primarily found in Northwestern (Idaho, Oregon, and Washington) and Midwestern (Minnesota and Wisconsin) parts of the of the United States. Symptoms include dark brown or purple streaking of the stems, pale and mottled leaves, wilting and dying off of the leaves, of plant tips, severe stunting, and the death of the plant. The pods may be spotted and distorted, purple-brown, and do not develop seeds. The virus can cause substantial crop loss and complete crop loss. The virus is transmitted by aphids and is not transmitted by seeds. The virus survives for long periods in infected alfalfa. Mild winter temperatures favor survival of the virus, thus the disease can be greater the following spring. The infected plants should be removed and burned to avoid further infestation. Plan on using a 3 year crop rotation and avoid planting in the same location, year after year. Avoid planting peas near alfalfa and removing red clover plants in the field. Insecticides for aphids can control the disease. The best option is to use disease resistant varieties.
PYMV
PVMV – Potato Yellow Mosaic Virus
Type: Virus - Begomovirus
Potato Yellow Mosaic Virus is a disease that affects the growth of peppers. Symptoms include yellowing of veins, leaf malformation, leaf mottling, and wrinkled or curled leaves. The peppers may have mottled and warty areas. There may be severe stunting of the plants, and sometimes death of plants. The virus can cause substantial crop loss. The virus is transmitted by aphids. Once the plant is infected, it can be spread by farm equipment, workers, clothing, and contaminated tools. The virus survives for long periods in infected weeds. Mild winter temperatures favor survival of the virus, thus the disease can be greater the following spring. The infected plants should be removed and burned to avoid further infestation. Plan on using a 3 year crop rotation and avoid planting in the same location, year after year. Avoid working in the garden during damp conditions as it can easily spread when plants are wet. Insecticides for aphids early in the season can control the disease. Keep the fields weed free. The best option is to use disease resistant varieties.
PVY
PVY – Potato Virus Y
Type: Virus - Potyvirus
Potato Virus Y is a disease that affects the growth of peppers. Symptoms include green mosaic on leaves, leaf malformation, and leaf mottling. There may be severe stunting of the plants, and sometimes death of plants. The virus can cause substantial crop loss. The virus is transmitted by aphids. The virus survives for long periods in infected weeds. Mild winter temperatures favor survival of the virus, thus the disease can be greater the following spring. The infected plants should be removed and burned to avoid further infestation. Plan on using a 3 year crop rotation and avoid planting in the same location, year after year. Insecticides for aphids early in the season can control the disease. Keep the fields weed free. The best option is to use disease resistant varieties.
R
R - Rust
Scientific Name: Puccinia asparagi, Puccinia sorghi
Type: Fungus
Rust, also known as Common Rust, is a world-wide soil borne disease that affects the growth of asparagus, cantaloupes & melons, corn, and lettuce. It is one of the most destructive disease in growing asparagus in the United States. The disease affects the ferns on asparagus. Lesions develop and turn cream-orange color, then turn a reddish-brown color, then eventually turn a brick red or rust color. During the winter the lesions will turn a black color. Severe infestation stunts or kills young asparagus shoots. The infected plants should be removed to avoid further infestation. When corn is infected the disease affects the upper and lower leaf surfaces, where small specks appear on the leaves, then develops into small tan spots, and distinguished by cinnamon-brown pustules. These pustules blister and turn dark brown to black late in the season. Corn stalks are weakened and stalk rot potential increases. Significant damage to upper leaves results in significant yield losses. Common rust spreads by windblown spores. The disease is also favorable cool and moist conditions when temperatures are 68-72 F, and usually occurs when there is nine hours of wet weather. The best option is to maximize air movement between the plants and to use disease resistant varieties.
RCVMV
RCVMV – Red Clover Vein Mosaic Virus
Type: Virus - Carlavirus
Red Clover Vein Mosaic Virus is a disease that affects the growth of peas. It is primarily found in United States, Europe, South Africa, Australia, and New Zealand. Symptoms include vein mosaic, streaking on stems and leaves, veins turning yellow or white, stunting, and the death of the plant. The pods may be distorted. The virus can cause substantial crop loss and complete crop loss. The virus is transmitted by aphids. The virus survives for long periods in infected plant debris. Mild winter temperatures favor survival of the virus, thus the disease can be greater the following spring. The infected plants should be removed and burned to avoid further infestation. Plan on using a 3 year crop rotation and avoid planting in the same location, year after year. Avoid planting peas near alfalfa and removing red clover plants in the field. Insecticides for aphids can control the disease. The best option is to use disease resistant varieties.
RZ
RZ – Rhizoctonia Root & Crown Rot
Scientific Name: Rhizoctonia solani
Type: Fungus
Rhizoctonia Root & Crown Rot is a world wide soil borne disease that affects the growth of beets. When the plant is infected, the leaves begin to wilt and the root system begins to rot. It can affect seedlings with damping-off problems, and the seedlings will wilt and often die. The crown on the beet root will rot, at or below the surface. Above ground symptoms include stunted leaves, dull leaf color, and a sudden wilting of the leaves. The leaves will turn yellow and eventually die. As the disease progresses, cankers and cracks may develop in the roots and a brown rotting may be seen in these cracks. Dark brown or black lesions may also be seen on the roots. In the advance stages of the bacterial root rot, a smell of fermentation will also be present. The disease is favorable when temperatures are 70-95 F and usually occur in poorly drained soil and where moisture and humidity are very high. Plan on using a 3 year crop rotation and avoid planting in the same infested location, year after year. Fungicides can help manage the disease. Good air circulation and increasing space between the plants can help control and prevent the disease. The best option is to use disease resistant varieties.
S
S - Smut
Scientific Name: Urocystis cepulae or Urocystis colhici
Type: Fungus
Smut is a world-wide soil borne disease that affects the growth of cantaloupes & melons, leeks, onions, and shallots. Smut has not been found in chives and garlic. It is one of the most destructive disease in growing onions in northern parts of the United States. The disease infects plants only when they are seedlings, killing the plants early in the season. Symptoms of smut include black streaks, blisters, or lesions appearing on the young leaves near the bulbs. A black powdery spore mass will be released when the bulbs rupture. Cold damp weather in the spring can make the seedling acceptable to the disease. Once affected by the disease, most of the seedlings will die in 3 to 5 weeks after germination. Infected plants may survive in a weaken condition, but the plant growth will be stunted, and the plant will die slowly. The infected plants should be removed and burned on the spot to avoid further infestation. The disease is also favorable when temperatures are 61-72 F, and usually occur in the spring. If the soil temperature is above 84%, when the seedlings are susceptible to the disease, there is usually no infection. Plan on using a 3 year crop rotation and avoid planting onions in the same location, year after year, as the disease can survive in the soil for a long time, up to 15 years. The smut disease can be transmitted from one field to another by water, by wind, and by farm equipment. Once the soil is infected, only seeds treated with fungicide should be planted. The best option is to use disease resistant varieties.
SCLB
SCLB – Southern Corn Leaf Blight
Scientific Name: Bipolaris maydis (Cochliobolus heterostrophus)
Type: Fungus
Southern Corn Leaf Blight is a fungal disease that affects the growth of corn and is considered the most devastating disease of corn crop. Southern corn leaf blight occurs commonly in the Southeastern regions of the United States. Symptoms are tan colored lesions on the leaves measuring 1/8 to 1/4 inch wide by 1/8 to 1 inch long. The diamond-shaped elongated shaped lesions begin on the lower leaves and then spread to upper leaves. The disease can cause significant loss of leaves. It can cause significant yield loss in corn. Losses are greater and more severe when plants are infected at the early stage of growth. The disease will spread by rain or wind. The disease is favorable when temperatures are 68-89 F and usually occur when moisture and humidity are very high. Plan on using a 3 year crop rotation and avoid planting in the same location, year after year, as the disease can survive in over winter on corn leaf debris. Proper tillage practices may be helpful in managing the disease. Fungicides can help manage the disease. The best option is to use hybrid disease resistant varieties.
SLS
SLS – Septoria Leaf Spot
Scientific Name: Septoria lycopersici
Type: Fungus
Septoria Leaf Spot is a soil-borne disease that affects the growth of tomatoes. It is one of the most destructive diseases of tomato foliage in wet and humid weather persists for extended periods. The symptoms include dark brown spots with tan or gray centers on the leaves, then the leaves turn yellow and brown and wilts. The disease can cause substantial yield loss and total crop loss. It is spread by farm equipment, tools, workers, wind, and water. The infected plants should be removed and burned to avoid further infestation. The virus can live in plant debris and in the soil. The disease is favorable when temperatures are 60-80 F and usually occur when moisture and humidity are very high. Plan on using a 1 to 2 year crop rotation and avoid planting in the same location, year after year, and can survive in the soil for 1 year. Apply fungicides at 7 to 10 day intervals can help manage the disease and will protect new leaves from becoming infected. Keep the fields weed free. Stake plants to improve air circulation. Use drip irrigation to keep foliage dry and avoid overhead irrigation. Mulching will reduce splashing soil, which may contain the disease.The best option is to use virus-free seeds and disease resistant varieties
St
St – Stemphylium Gray Spot Leaf
Scientific Name: Stemphylium solani, Stemphylium floridanum, and Stemphylium botryosum
Type: Fungus
Stemphylium Gray Spot Leaf is a fungal disease that affects the growth of tomatoes. It is found in warm regions of the country, and is common in the Southeastern part of the United States. Symptoms include brown to black specks on leaves. As the lesions grow in size, they develop a gray center surrounded by a yellow area. The spots may dry and fall out, forming a shot hole in the leaf. The disease may cause the entire leaves to turn yellow, then brown, and drop off, and the plant may be stunted. The tomatoes are not usually affected unless there is severe defoliation, where sunburn damage can occur on the tomatoes. If you stick with Stemphylium Gray Spot Leaf Resistant tomato varieties you don’t have to worry. Many of the older heirlooms don’t have any resistance to the disease, so if you grow these then you should keep an eye out for it. The infected plants should be removed and burned to avoid further infestation. Plan on using a 5 to 7 year crop rotation and avoid planting in the same location, year after year, as the disease can survive in the soil for many years. Stake tomato plants for better circulation. Give plants extra space to allow air to move among leaves to keep leaves as dry as possible. Use soaker hoses and avoid overhead watering. The best option is to use disease resistant varieties.
Stp
Stp – Stip
Type: Physiological Disorder
Stip affects the growth of peppers. Symptoms include black, brown, green, or gray spots developing on the peppers and is caused by calcium deficiencies. The spots usually occur on mature peppers. The affected peppers become unmarketable. It can cause substantial crop loss. Calcium applications can help reduce the occurrence and severity of stip. The best option is to use disease resistant varieties.
SW
SW - Stewart's Wilt
Scientific Name: Erwinia stewartii
Type: Bacterium
Stewart's Wilt is a disease that affects the growth of corn. Stewart's wilt is common throughout the eastern regions of the United States. The disease is transmitted to corn plants during feeding by adult corn flea beetles. These beetles overwinter in the soil and upon emergence in the spring, commence feeding on the plants, and contaminates corn seedlings. An entire field of corn may become infected in a relatively short period of time. Some or all of the plants may die, and severe yield reductions result. The bacteria is carried in the digestive tract of the corn flea beetle. Beetles feeding on infected corn tissue acquire the bacteria and spread it further. Wilting of foliage is often associated with the infection, plants may be stunted, and in severe cases, death may result. When seedlings and young plants are infected, they will wilt and the main stalks may die. Symptoms include lesions on the leaves. The lesions appear as long wavy streaks that turn yellow and eventually brown. Entire leaves may die if the disease is severe and the stalks may develop fungal rot and become weaken. The disease can cause substantial yield loss due to leaf damage and weakened plants resulting from stalk rot. The infestation year to year depends largely on winter temperatures, and how many beetles carrying the disease survive the winter. Mild winter temperatures favor survival of the beetle, thus the disease can be greater the following spring. When winter temperatures are greater than 24°F during a two month period, a moderate to high risk of Stewart’s wilt is possible. Beetles carrying the bacteria that survive the winter could infect corn plants next spring. Insecticide treatments helps reduce flea beetle populations. The best option is to use hybrid disease resistant varieties.
TB
TB - Tip Burn
Type: Physiological Disorder
Tip Burn is caused by inadequate transport of calcium to rapidly growing tissues. It has caused severe loses to growers in the United States and Europe. It affects Brussels sprouts, cabbage, cauliflower, kohlrabi, and lettuce. Uneven rainfall and watering, high temperatures, high humidity, windy conditions, dry soil conditions, and rapid growth are all factors. Tip burn consists of a breakdown of the plant tissue near the center of the head and develops as
the crop approaches maturity. The inner leaves of heads of cabbage are affected, often without external symptoms. The inner leaves turn dark brown, then to a black color. Symptoms can extend from a few small brown spots on interior leaf edges, to large areas of the leaf turning brown and eventually decaying. Secondary rot caused by bacteria can follow tip burn and heads of cauliflower can be severely affected. No completely effective controls are known, but excessive soil moisture and insufficient soil moisture have both been suspected as contributing to a calcium deficiency. Managing irrigation can regulate and control plant growth and calcium deficiency. The best option is to use varieties resistant to tip burn.
TEV
TEV – Tobacco Etch Virus
Type: Virus - Potyvirus
Tobacco Etch Virus is a disease that affects the growth of peppers. This disease is most common in Canada, the USA (including Hawaii), Mexico, Puerto Rico, and Venezuela. Symptoms include crinkling of leaves, reduction in size of leaves, leaves are distorted and mottled, vein clearing, necrotic lines or etching, and severe stunting of the plant. Peppers are mottled and do not reach full size. In severe cases, wilting and death of the plant can occur. The virus can cause substantial crop loss. The virus is transmitted by aphids and can spread mechanically. The virus survives for long periods in plant debris. Mild winter temperatures favor survival of the virus, thus the disease can be greater the following spring. The infected plants should be removed and burned to avoid further infestation. Plan on using a 3 year crop rotation and avoid planting in the same location, year after year. Keep your garden weed free. Disinfect tools, stakes, and equipment. Wash clothing that comes into contact with the infected plants. Use screen house with 32 mesh or greater to keep out aphids. Insecticides for aphids can control the disease. The best option is to use disease resistant varieties.
TH
TH – Thrips
Type: Insect
The onion thrips is a common insect pest of onions. The insect is present throughout the United States. It is one of the most destructive insect pests in growing onions in Washington State. Besides onions, they feed on numerous vegetables including: cabbage, potato, and tomato. Thrips damage onions by puncturing the leaves and sucking up the sap. The damage causes the leaves to dry up, wither, turn brown, and eventually cause the stalk to bend and break. If thrips are feeding on cabbage, the cabbage will be blistered, scarred, and bronzed by thrips feeding on the leaves. Where many thrips had fed, discolored brownish blister-like areas will be visible. Lacewings, lady bugs, and parasite wasps may help regulate the thrips population. Insecticides have helped in controlling thrips in the past, but its rapid resistance to insecticides has been a problem. The best option is to use thrips tolerant varieties.
TLS
TLS – Target Leaf Spot
Scientific Name: Corynespora cassiicola
Type: Fungus
Target Leaf Spot is a world-wide fungal disease that affects the growth of cucumbers. Symptoms include lesions of angular yellow spots on leaves. The spots become larger and circular with light brown center and dark brown borders. The spots eventually turn gray and the leaves will eventually die off and the whole plant becomes defoliated. The most damaging aspect of scab is on the fruit. Small sunken spots appear on the cucumbers. The infected plants should be removed to avoid further infestation. The disease is favorable when temperatures are 77 - 85 F when moisture and humidity are very high. The fungus can remain on infected plants and weeds for 2 years. Fungicides can help manage the disease. The best option is to use disease resistant varieties.
TMV
TMV – Tobacco Mosaic Virus
Type: Virus - Potyvirus
Tobacco Mosaic Virus is a world-wide virus disease that affects the growth of eggplants, peppers, and tomatoes. Tobacco mosaic virus may cause significant losses in the field and in the greenhouse. The virus does not usually kill the plant, but it does cause damage to flowers, leaves, and the tomato. Symptoms include stunted or dwarfed plants, yellow-green mottling, blistering of the leaves, a light-green and dark-green mosaic pattern on the leaves, leaf distortion and curling of the leaves, fernleafing, and reduced growth rate and yields. Blooms may have brown streaks. Pepper plants may have yellow spotting on the leaves. Slightly sunken brown rings will appear on tomatoes. The virus is spread primarily by mechanical methods. The virus is not spread by aphids. Smokers can infect plants by handling them. Gardeners contaminate the plants when they touch tobacco products or infected plants or weeds and spread the virus to healthy plants. The virus can stay alive in dead plant material for long periods of time. It can survive on infected seeds, plant debris, and even clothing for months or years. Tobacco mosaic is one of the most highly persistent tomato diseases because it can remain viable for many years and is able to withstand high heat. The virus can survive for up to 50 years in dried plant debris. The infected plants should be removed and buried or burned to avoid further infestation. Plan on using a 3 year crop rotation and avoid planting in the same location, year after year. Keep your garden weed free. Wash your hands thoroughly and disinfect tools. Try to avoid smoking while working in the garden. Spraying plants with 20 percent nonfat dry milk has been shown to be somewhat effective in preventing the spread of the virus. The best option is to use disease resistant varieties.
ToMV
ToMV – Tomato Mosaic Virus
Type: Virus - Tobamovirus
Tomato Mosaic Virus is a world-wide virus disease that affects the growth of peppers and tomatoes. Symptoms include dark green mottling or mosaic appearance on the leaves, yellowing of leaves, and stunting of the plant. The leaves tend to be fern-like and younger leaves may be twisted. The tomatoes will will be deformed and have yellow spots and the interior is brown. Infected plants usually wilt and die. It can cause significant yield loss and even total crops losses. It is a seed-borne virus and can be spread by farm equipment, workers, clothing, and contaminated tools. The disease can stay alive in dead plant material for long periods of time. The infected plants should be removed and destroyed to avoid further infestation. Plan on using a 2 year crop rotation and avoid planting in the same location, year after year, as the disease can survive in over winter on crop debris for 50 years. Keep your garden weed free. The best option is to use disease resistant varieties.
TSWV
TSWV – Tomato Spotted Wilt Virus
Type: Virus - Tospovirus
Tomato Spotted Wilt Virus is a world-wide virus disease that affects the growth of peppers and tomatoes. Symptoms include bronzing of the upper sides of young leaves, which later develop distinct yellow or brown rings. Leaves may curl inward. The plants will be stunted and have dark streaking on stems. The tomatoes will be deformed. There will be mottled light green rings with raised centers with orange and red discoloration patterns on mature tomatoes making them unmarketable. Infected plants usually wilt and die. It can cause significant yield loss and even total crops losses. The virus is spread by thrips. The disease can stay alive in dead plant material for long periods of time. The infected plants should be removed and destroyed to avoid further infestation. Plan on using a 3 year crop rotation and avoid planting in the same location, year after year. Insecticides for thrips have limited value in controlling the disease as thrips transmit the disease very quickly when they begin to feed on the plant. To control thrips, try setting out yellow or blue colored sticky traps and treat plants with insecticidal soaps. Keep your garden weed free. The best option is to use disease resistant varieties.
TYLCV
TYLCV – Tomato Yellow Leaf Curl Virus
Type: Virus - Geminivirus
Tomato Yellow Leaf Curl Virus is a disease that affects the growth of tomatoes. It is primarily found in California and Florida. Symptoms include severe stunting, yellowing of leaves, reduction in leaf size, and leaves curling upwards. Flowers do not develop fully and fall off. Tomatoes will drop off the infected plants. Severe infection can lead to the death of the plant. The disease can cause substantial yield loss and total crop loss. It is spread by the whitefly. The disease does not survive in soil, but can survive in weeds, so use weed management techniques. Plan on using a 3 year crop rotation and avoid planting in the same location, year after year. Keep the fields weed free. Proper tillage practices may be helpful in managing the disease. Covering plants with floating row covers of fine mesh can help protect plants from whitefly infestations. Home gardeners should carefully cover the plant with a plastic bag and tie at the stem at soil line to collect the entire plant and any whiteflies that may be on the plant, then cut off the plant at the soil line. Dispose of the plastic bag in the trash. Insecticides for can help control whitefly infestation. The best option is to use virus-free seeds and disease resistant varieties.
TuMV
TuMV – Turnip Mosaic Virus
Type: Virus - Potyvirus
Turnip Mosaic Virus is a disease that affects the growth of turnips. Symptoms include light green circular and irregular lesions on leaves, leaves are distorted and mottled, blistering, and stunting of the plant. Black spots develop on leaves which prematurely drop which leads to defoliation. The virus can cause substantial crop loss. The virus is transmitted by aphids and is not transmitted by seeds. The virus survives for long periods in plant debris. Mild winter temperatures favor survival of the virus, thus the disease can be greater the following spring. The infected plants should be removed and burned to avoid further infestation. Plan on using a 3 year crop rotation and avoid planting in the same location, year after year. Insecticides for aphids can control the disease. The best option is to use disease resistant varieties.
ULS
ULS – Ulocladium Leaf Spot
Scientific Name: Ulocladium cucurbitae
Type: Fungus
Ulocladium Leaf Spot is a world-wide fungal disease that affects the growth of cucumbers. Symptoms include lesions of reddish brown spots on leaves. The spots become larger and circular to irregular in shape with the center is beige to brown surrounded by a dark brown ring and a brown halo. The infected plants should be removed to avoid further infestation. The disease is favorable when temperatures are 70 - 81 F in early to mid-August when moisture and humidity are very high. Plan on using a 2 year crop rotation and avoid planting in the same location, year after year, as the disease can survive over winter on crop debris and soil for 2 years. Fungicides can help manage the disease. The best option is to use disease resistant varieties.
V
V – Verticillium Wilt
Scientific Name: Verticillium dahliae
Type: Fungus
Verticillium Wilt is a soil-borne disease that affects the growth of lettuce, peppers, spinach, and tomatoes. This disease is most common in the United States and Europe. In lettuce symptoms include wilting of the lower leaves and then the outer leaves turn yellow, wilt and die. Brown and black streaks appear on the taproot and crown The disease can cause substantial yield loss and total crop loss. It is a seed-borne disease that is spread by farm equipment, wind, and water. The infected plants should be removed and burned to avoid further infestation. The virus can live in weeds, so use weed management techniques. The fungus is very difficult to eradicate once it has been introduced into a field. Plan on using a 4 year crop rotation and avoid planting in the same location, year after year, and can survive in the soil for 14 years. Keep the fields weed free. Deep tilling may be helpful in managing the disease. Thoroughly clean equipment after working in a field. Fumigate fields with methyl bromide. The best option is to use virus-free seeds and disease resistant varieties
WMV
WMV – Watermelon Mosaic Virus
Type: Virus - Potyvirus
Watermelon Mosaic Virus is a virus disease that affects the growth of cantaloupes & melons, cucumbers, gourds, pumpkins, squash, and watermelons. Watermelon mosaic virus is primarily a problem in the southern and western regions of the United States. Symptoms include stunted or dwarfed plants, yellow or light green mottling, blistering, marginal yellowing, leaf distortion, and reduced growth rate and yields. Losses of 50 percent or more in yield and fruit quality may occur. The fruit frequently show color breaking and warts. It is only spread by aphids. Symptoms usually begin to show in June. Plan on using a 3 year crop rotation and avoid planting in the same location, year after year. Plastic mulches have been shown to reduce losses. Insecticides for aphids are of limited value to control the disease. The best option is to use disease resistant varieties.
ZYMV
ZYMV – Zucchini Yellow Mosaic Virus
Type: Virus - Potyvirus
Zucchini Yellow Mosaic Virus is a world-wide virus disease that affects the growth of cantaloupes & melons, cucumbers, gourds, pumpkins, squash, and watermelons. Symptoms include stunted or dwarfed plants, mottling, yellowing, distortion, blistering, and wrinkling of the leaves, and reduced growth rate and yields. The virus can cause total crop lose. The symptoms on leaves known as "shoestring" effect causes young leaves to appear narrow, and fern-like appearance of the leaves. The virus causes cucumbers to become bumpy and oddly shaped, and have a bitter taste. Cantaloupes & melons and watermelons are malformed and often develop deep cracks. Squash and pumpkins can develop knobby areas. Plants infected with the virus have little or no marketable fruit. The virus can reduce yields and fruit quality. It is spread by aphids and seeds. The infected plants should be removed to avoid further infestation. Plan on using a 3 year crop rotation and avoid planting in the same location, year after year. Keep the fields weed free. Proper tillage practices may be helpful in managing the disease. Insecticides for aphids are of limited value to control the disease. Using transparent or silver plastic mulches have been shown to repel aphids and delay the virus from spreading. Ladybird beetles can be effective at naturally controlling aphid populations. The best option is to use disease resistant varieties.