Jim,
Root Knot Nematodes are a serious problem for us here in Florida. The soil never freezes so the little buggers just keep on producing.
These microscopic "eels" get into the roots of plants and form "galls" or "knots" that strangle the host plant. Nematodes mostly effect fruiting vegetables like peppers, tomatoes, and eggplants. (For tomatoes, plant "VFN" resistant varieties.) Nematodes can also be a problem for cukes but it does not sound like that's your problem. Nematodes are disasterous to citrus! Please be careful about carrying contamination on tools on in soil to any orange trees.
As RogerX suggested, examine the roots of the plants you pull up for tiny knots. If you do find an abundance of knots, destroy infected rootstock, DO NOT COMPOST! Be careful about spreading them, wash your tools.
There are several things you can do to contol nematode infestation:
You can no longer use Vapam but you can solarize the soil for a couple of months, that helps.
You can try to flood them out. I have actually dug up infected beds and soaked the soil in 55 gal drums.
Add LOTS of organic material. There is some fungus found in compost that chokes the nematode. That fungus thrives in composted pine needles and, get this, crustacion shells like shrimp or crabs.
Add the product, "Nemagone." It's expensive and it is made from ground-up crab shells. "Chitten" (Or something like that.)
Add Sugar. That's a weird one from a Rodale book. Be sure to water the sugar thru prior to planting.
Plant Mexican Marigolds. They repell nematodes and other pest.
Water with Asparagus liquor. Yep, save the water when you cook asparagus and dump it on the plants.
Good luck,
Ed Upshaw
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