Q: I think I have nematodes in my vegetable garden. Last year my plants did poorly and were stunted. The roots were knobby. Is there anything I can do this year?

A.H.,

North Miami

A: Starting now before you plant your vegetable garden, place clear plastic over your vegetable bed after wetting the area thoroughly. Hold down the plastic with rocks or bricks to get a good seal along the edges of the bed and plastic. Leave the plastic in place for at least six weeks. Then remove and plant your garden.

Incorporate a lot of organic matter such as compost into your soil to reduce nematode populations. Mulching throughout the growing season may also help. Try to plant nematode-resistant varieties. Resistant varieties will have the letter N on the seed packet or plant label.

If you want to keep your garden productive during the summer, grow southern peas (aka field peas, or cow peas) as a cover crop. `California No. 5 Blackeye' has been proven to be resistant to root-knot nematodes. Eat these peas in the snap, green-shell or dry-seed stage.

Plants affected by plant-parasitic nematodes show leaf symptoms similar to those caused by inadequate moisture, poor nutrition or root rot. Affected plants may be stunted and have pale or yellow-green foliage. They may wilt readily under warm breezy conditions even when soil moisture is adequate.

Most vegetables can be attacked by root-knot nematode. Some of the most susceptible crops: tomatoes, okra, beans, squash, peppers, carrots, cucumbers, melons and eggplant. These vegetables are fairly resistant to root-knot nematodes: broccoli, mustard and chives.

Adrian Hunsberger is an entomologist/horticulturist with the UF/IFAS Miami-Dade Extension office. Write to Plant Clinic, 18710 SW 288th St., Homestead, FL 33030; e-mail aghu@ifas.ufl.edu.