Excursion II Sweet Peppers

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.

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.

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.

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.