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.
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.