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.
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.