Corn nematode buzz continues to heat up as production practices include less crop rotation and seed treatments to control nematodes come to market.
While you may be concerned about the current crop, you need to think a year ahead to get on top of corn nematodes. Now is the time to start soil sampling to determine if you have a problem and what to do about it in 2012.
Tamra Jackson, University of Nebraska-Lincoln plant pathologist says growers should be sampling for corn nematodes early in the season, when roots are still shallow and in the upper 8-inches of the soil. She says during most seasons the roots and root feeding nematodes should be in reach of soil sampling probes about four to eight weeks after planting. Some corn nematodes travel deeper in the soil during the growing season and may be out of reach if you wait too long.
Guidelines for collecting samples for plant parasitic nematode analysis can vary between states, so check with local extension personnel to determine where and how to submit samples. Most land grant institutions have quality nematology labs. There are also many good commercial labs across the country. Nematodes in your sample need to be alive for an effective analysis and a plant sample is typically requested in addition to a soil sample.
Although nematode injury to corn is fairly common, it can be hard to identify. For example, nematode damage to corn roots can be easily mistaken for herbicide injury. Aboveground nematode damage symptoms can include stunting, yellowing, midday curling of leaves, swollen roots and small ears with poor grain fill. On the other hand, there may be no obvious aboveground symptoms, but significant yield losses can still result from the pest.