Spotting corn nematode damage – it’s not easy

Published on: 15:12PM Jul 28, 2009

Corn parasitic nematodes, microscopic, thread-like round worms that feed on roots, damage corn in several ways. However, because it is difficult to precisely identify nematode injury in corn, nematode feeding is often mistaken for different problems.

Nematode injury shows up as discoloration or chlorosis, stunting, root damage, reduction in stalk diameter and root weight, and more. But these symptoms are often misdiagnosed as herbicide injury, disease, micronutrient deficiencies or environmental stress from drought. 

Nematode damage also provides an entry point for other problems, such as viruses, bacteria and fungi, to invade corn plants. Some nematode species interact with other problems to intensify symptoms and yield loss. 

And sometimes there are no visual symptoms, but yield and profit are impacted by nematode feeding. The best way accurately identify levels of nematode damage is an on-farm trial or split field, comparing corn treated with a complete offer that includes nematicide, insecticide and fungicide to corn without a nematicide.