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.

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.

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.

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.

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.

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