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.