Diva Cucumber Seeds

ALS – Angular Leaf Spot

Scientific Name: Pseudomonas syringae pv. lachrymans

Type: Bacterium

Angular Leaf Spot is a world-wide bacterial disease that affects the growth of cantaloupes, melons, cucumbers, and squash. It can also affect strawberries. It is caused by the Pseudomonas syringae pv. lachrymans bacteria. Angular leaf spot thrives in warm, humid conditions. Symptoms may first develop on young plants where small angular spots develop that turn brown or straw-colored. Under humid conditions, milky white liquid may appear on the spots. The disease can also affect the stem and cause the fruit to rot. The disease expands during rainy weather and temperatures of 75 to 82 degrees F. The infected plants should be removed to avoid further infestation. Avoid working among plants when foliage is wet and use overhead irrigation when possible. 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 years. Pesticides can help manage the disease. The best option is to use disease-resistant varieties.

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.

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 – 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.

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.