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Know Conditions That Favor Nematode Buildup

corn nematodes

Nematodes have been called the ‘silent yield thieves’ — photo courtesy Alabama Cooperative Extension System

In corn fields, wet weather in April is a recipe for nematode problems—specifically cotton root knot and stubby root nematodes. While not widely recognized as a yield-reducing pest in corn, the root knot nematode is a pest that affects both cotton and corn.

Austin Hagan, an Alabama Cooperative Extension System plant pathologist, said the cooler April weather in 2018 was conducive to the growth and support of the nematode population.

“In a multi-year rotation study at the Plant Breeding Unit a decade ago, yield losses in corn of up to 30 percent were attributed to the cotton root knot nematode,” Hagan, who is also a professor in the Auburn University Department of Entomology and Plant Pathology, says. “The study shows yield declines of 4 to 11 percent correlate with every 100 cotton root knot juveniles in a fall nematode soil assay.”

The impact of stubby root nematode on corn yield is still unknown, and stunting can be dramatic but tends to be localized. Producers may see patchy, stunted areas in corn, easily confused with fertility and pH issues.

Wiregrass Regional Extension Agent, Brandon Dillard, suggests producers put out a nematicide as they were planting corn, particularly if fields have a lot of moisture from rainy weather.

After planting, there is little producers can do to combat nematode pressure. Producers should aim to optimize fertility and supplement a moisture deficit with irrigation to minimize stress and encourage root growth. Fertilization and irrigation will help offset feeding injury to the root system.

“There are no post-plant nematicides labeled for use in corn,” Hagan says. “Ongoing research projects at several Alabama Agricultural Experiment Station research units are addressing this issue.”

Article provided by the Alabama Cooperative Extension Service.