Evergreen White Bunching Onion Seeds

PR - Pink Rot

Scientific Name: Phoma terrestris

Type: Fungus

Pink Rot is a devastating soil borne disease that affects the growth of onions and can occasionally affect corn, peppers, spinach, and soybeans. The disease started in North Carolina and the mid-Atlantic region and continues to spread to other areas. The disease affects the roots, where they become shriveled and deteriorate, and then may disintegrate. Symptoms of wilting of the leaves may occur and the leaves turn a pale green and start to die off. Onions infected with Pink Root often show a light pink color, then becoming a darker pink color, and progressing to a purple-brown color. The plant is rarely killed by the disease, but the bulbs never matures fully. The surviving plants are stunted and the bulb size is reduced and becomes soft and non-desirable. Cold weather, drought conditions, insect spreading the disease, nutrient deficiencies, and other diseases, can cause stress to the plant which can increase the severity of the disease. Plan on using a 6 year crop rotation and avoid planting onions in the same location, year after year as the disease can survive in the soil for a long time. The best option is to use disease resistant varieties and/or use a root fungicide for soil based diseases.

S - Smut

Scientific Name: Urocystis cepulae or Urocystis colhici

Type: Fungus

Smut is a world-wide soil borne disease that affects the growth of cantaloupes & melons, leeks, onions, and shallots. Smut has not been found in chives and garlic. It is one of the most destructive disease in growing onions in northern parts of the United States. The disease infects plants only when they are seedlings, killing the plants early in the season. Symptoms of smut include black streaks, blisters, or lesions appearing on the young leaves near the bulbs. A black powdery spore mass will be released when the bulbs rupture. Cold damp weather in the spring can make the seedling acceptable to the disease. Once affected by the disease, most of the seedlings will die in 3 to 5 weeks after germination. Infected plants may survive in a weaken condition, but the plant growth will be stunted, and the plant will die slowly. The infected plants should be removed and burned on the spot to avoid further infestation. The disease is also favorable when temperatures are 61-72 F, and usually occur in the spring. If the soil temperature is above 84%, when the seedlings are susceptible to the disease, there is usually no infection. Plan on using a 3 year crop rotation and avoid planting onions in the same location, year after year, as the disease can survive in the soil for a long time, up to 15 years. The smut disease can be transmitted from one field to another by water, by wind, and by farm equipment. Once the soil is infected, only seeds treated with fungicide should be planted. The best option is to use disease resistant varieties.

TH – Thrips

Type: Insect

The onion thrips is a common insect pest of onions. The insect is present throughout the United States. It is one of the most destructive insect pests in growing onions in Washington State. Besides onions, they feed on numerous vegetables including: cabbage, potato, and tomato. Thrips damage onions by puncturing the leaves and sucking up the sap. The damage causes the leaves to dry up, wither, turn brown, and eventually cause the stalk to bend and break. If thrips are feeding on cabbage, the cabbage will be blistered, scarred, and bronzed by thrips feeding on the leaves. Where many thrips had fed, discolored brownish blister-like areas will be visible. Lacewings, lady bugs, and parasite wasps may help regulate the thrips population. Insecticides have helped in controlling thrips in the past, but its rapid resistance to insecticides has been a problem. The best option is to use thrips tolerant varieties.