Root rot in vegetables strikes quickly and can ruin an entire crop, notes Cornell University. You can try to treat this disease, but the best course of action is preventative measures, as treatment with fungicide does not always work. Not all vegetables can contract root rot, but many common vegetable crops are susceptible.
Vegetables in the cucurbit family can contract root rot. This family includes pumpkins, squash, cucumber and melon. Other vegetables that get this disease but are not in the cucurbit family are peppers, eggplant and tomatoes. Cornell University notes that vegetable root rot can attack the plant's roots, stems, leaves or fruit/vegetable, depending on when the plant becomes infected.
Affected vegetables first develop a blotchy spot that looks water-soaked. Sometimes, the spots grow fungus, and occasionally, vegetables develop depressed indentations. Gardeners can easy pierce the vegetable skin at the blotch. Vegetables that have fungus soon become covered in white fungal growth. Over time, the vegetables wither on the stem but they do not drop. Inside, the seeds shrivel.
This fungal disease is caused by Phytophthora capsici and goes by many names, including Phytophthora blight, Phytophthora root rot, damping off and fruit blight. Warm, wet weather and too much moisture in the soil combine to bring on this disease.
Cornell University notes that vegetable root rot has occurred in New York periodically over the last 40 years and also occurs in Florida, New Mexico, New Jersey and California, where it occurs more frequently. This disease was first reported in the 1930s.
You can treat root rot with fungicides, but check with a local county extension office to find out which fungicides are approved to combat vegetable root rot. This disease spreads quickly, so waiting too long to treat it may mean your efforts are too late.
Preventative measures against Phytophthora root rot include rotating crops every three years and planting crops that are resistant to this disease where susceptible crops grew. Avoid watering during periods of heavy rainfall and only plant vegetables in well-draining soil. Growing in raised beds that have sides that slope down allows excess water to roll off the bed.