Having Problems Controlling Vegetable Crop Diseases – Try Rotation

We are increasingly encountering a variety of difficultly to control plant diseases in vegetable fields. One management tool that could be used more widely to help in the control of plant diseases is rotation. Many diseases build up in the soil when the same crop is grown in the same field year after year. Rotation can help break this cycle and stop the buildup of disease organisms in the field. To be effective, rotations must be carefully planned. The present crop and all related plants or alternate hosts for the disease must be kept out of the field. Only those crops not susceptible to the disease should be grown there. Different plant diseases will persist in the soil for different lengths of time, so the length of the rotation will vary with the disease being managed. The following table lists many of the vegetable crop diseases that can be affected by rotation and the length of rotation that is required.

Rotation Periods Suggested to Help Control Vegetable Diseases
Vegetable Disease Period Without a Susceptible Crop
Asparagus Fusarium wilt, root rot Indefinitely; do not replant without fumigation
Beans Root rots Several years
Pod white mold Several years, avoid potato, tomatoes, lettuce, cabbage
Anthracnose Two years
Bacterial blight Two years
Beets Cercospira leaf spot Three years
Cabbage-related plants Clubfoot Seven years; avoid turnip and radish
Fusarium yellows Many years
Blackleg Three to four years; avoid turnip
Black rot Two to three years; avoid turnip
Carrots Leaf blights Few years
Celery Leaf blights Few years
Corn, sweet Smut Few years
Yellow leaf blight Three years
Northern corn leaf blight Few years
Cucumber Scab and leaf spot Two years
Eggplant Verticillium wilt Four years; avoid tomato, potato, pepper, strawberry, brambles
Fruit rots Three years
Lettuce Bottom rot and drop Three years
Muskmelon Leaf spots Two plus years; avoid watermelon, pumpkin and squash
Scab Two plus years; avoid cucumber, pumpkin and squash
Fusarium wilt Several years. Disease is different from watermelon fusarium wilt
Vegetable Disease Period Without a Susceptible Crop
Onion Leaf blights One to two years
Parsley Damping-off Three years
Parsnip Leaf spot and root canker One to two years
Peas Root rots Three to four years
Fusarium wilt Four to five years
Peppers Bacterial spot One to two years
Phytophthora blight Two years; also avoid tomato and eggplant
Potato Verticillium wilt Three to four years without tomatoes
Sclerotinia stalk rot Four years
Rhizoctonia canker Two to three years, preferably with two grasses or one cereal
Pythium leak and pink rot Four years
Common scab Three to four years; no root crops
Pumpkin & Squash Black rot Two plus years; avoid muskmelon and watermelon
Radish Clubfoot Seven years; avoid turnip and cabbage-related plants
Turnip Clubfoot Seven years; avoid radish and cabbage-related plants
Spinach Downy mildew Two years
Sweet potato Black rot and scurf Three years
Pox Few years
Tomato Bacterial canker Three years
Bacterial speck One year
Bacterial spot Two years; avoid pepper
Early blight Two years; avoid potato
Anthracnose Two plus years
Fusarium wilt Three years
Verticillium wilt Several years; as long as possible; avoid potato
Watermelon Black rot Two plus years; avoid muskmelon, pumpkin and squash
Fusarium wilt Several years. Disease is different from muskmelon fusarium wilt

Originally from: Vegetable Newsletter, Vol. 19, No.4, Pennsylvania State University, A. MacNab, April 1990.

Revised by: Richard A. Ashley, Extension Specialist – Vegetables, April 1994.

Reviewed by: T. Jude Boucher, UConn IPM, 2012

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