After the hot summer, many farmers are facing crops that may have under-performed due to the weather. But bare spots, excessively weedy areas or crops that look stunted, discolored or wilted may also signal a problem with plant-parasitic nematodes.

Nematodes are microscopic worms, most of which live in soil. Now is a good time to scout fields for problems, collect samples and do some troubleshooting. It won’t help the current crop, but you’ll be able to plan better for the next one.

“Nematodes tend to be hidden pests,” said Weimin Ye, nematologist with the North Carolina Department of Agriculture and Consumer Services. “They damage roots and interfere with the uptake of water and nutrients. The injury is not obvious right away. However, in late summer, populations peak and symptoms are more apparent.”

Identifying nematode problems is difficult because, in most cases, there is no single, easily recognizable symptom. General problems such as wilting, discoloration, stunting, patchy growth or weed prevalence can all indicate a nematode infestation, but none of these symptoms are definitive. The surest way to diagnose a nematode problem is to collect soil and root samples and send them to the NCDA&CS nematode assay lab, said Ye.

Although nematodes can occur in all soils, crops growing in sandy soils are particularly vulnerable to damage. For this reason, growers in eastern counties are advised to test their fields annually. For a minimal fee ($3 for North Carolina samples and $10 for out-of-state samples), a Nematode Assay Report by the NCDA&CS Agronomic Division can provide valuable information about your soil such as the species of plant-parasitic nematodes present, their relative abundance, the degree of hazard they pose to the specified crop and best management practices, if necessary.