Nematodes are microscopic worms that live in the soil. They are not related to earthworms. Nematodes feed on grass roots, damaging and stunting them. The damaged roots can't supply sufficient water and nutrients to the leaf blades, and the grass is stunted or slowly dies. Nematodes are found throughout the country, but are most severe in the South. They prefer moist, sandy loam soils. They can move only a few inches each year on their own, but they may be carried long distances by soil, water, tools, or infested plants. Testing roots and soil is the only positive method for confirming the presence of nematodes. Contact your local County Extension Agent (see County Extension Agents) for sampling instructions and addresses of testing laboratories. Soil and root problems such as poor soil structure, drought stress, nutrient deficiency, and root rots can also produce symptoms of decline similar to those caused by nematodes. These problems should be eliminated as causes before sending soil and root samples for testing. (For information on soil problems and root rots, see Water Molds.)
There are no chemicals available to homeowners to kill nematodes in planted soil. However, they can be controlled before planting a new lawn by soil fumigation. (For information on fumigating soil, see Soil Fumigation and Solarization.)
