Resistant tomato varieties adapted to Oklahoma are not currently available, but are being developed. Nematodes are microscopic round worms that live in soil. Some nematode species feed on plant roots and cause diseases. Repeated cropping of susceptible crops may result in nematode populations rising to levels that cause economic damage. Reduced plant growth and yield result from the poor root development and function caused by nematode feeding.
Nematodes are most damaging in warm sandy soils.
Poorly drained soils with high clay content often do not support high nematode populations. Low population levels generally do not cause damage and may even stimulate plant growth. Root-knot is the most important nematode disease of tomato in Oklahoma. Four kinds of root-knot nematodes commonly affect tomatoes and many other crop plants. These are the southern, northern, peanut, and javanese root-knot nematodes.