A Cook's Garden by Barbara Damrosch: Latest Column and Archive - The Washington Post I especially like the Seafood Feast for your garden article. It gives hope for heading off root knot nematode infested soil.
Marigolds: Why plant them in your garden? "Annual Marigolds can be used anywhere to deter Mexican bean beetles, squash bugs, thrips, tomato hornworms, and whiteflies. They are also known to repel harmful root knot nematodes that attack tomatoes, potatoes, roses, and strawberries. The root of marigolds produces a chemical that kills nematodes as they enter the soil. If a whole area is infested, at the end of the season, turn the Marigolds under so the roots will decay in the soil."
Peanut roots with galls caused by root-knot nematode. Galls are difficult to distinguish on peanut roots because N-fixing nodules cover the roots. Galls are thickenings of the roots while nodules are round attachments to the side of the roots.