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Pest Profile: Root Lesion Nematodes

They've been called the "hidden enemy." Since they are almost impossible to detect without soil analysis by trained professionals, damage by root lesion nematodes in corn is often misdiagnosed as herbicide injury or nutrient deficiency.

Nematodes can decrease corn yields by 10 percent to 75 percent in severe instances.

In fact, corn plants could be suffering from restricted performance of their root systems caused by these pests. According to the University of Illinois Extension, overabundance of root lesion nematodes in the soil leads to damage that exacerbates other stresses faced by the plant.

"Very few farmers tell me they have a corn nematode problem," says Farm Journal Associate Field Agronomist Missy Bauer. "But we find nematode damage on many field calls. Often, it is misdiagnosed as something else, such as herbicide injury.”

An Invisible Drain on Yield

According to research by Ann MacGuidwin, PhD, a University of Wisconsin plant pathologist, root lesion nematodes can cause yield loss even without visible aboveground symptoms present.

She also reports that nematode damage is on the rise in corn, the result of a number of changes in farming practices. Rotation reduction is one example, with growers implementing more corn-on-corn rotation. Reduction in the use of organophosphate and carbamate insecticides is another. And with more planting of insect-resistant corn, there’s been a reduction in the use of at-plant soil insecticides, another contributing factor.

Protecting Corn Roots

Typically, root lesion nematodes move deeper into the ground, out of the reach of tillage, two to three weeks into the growing season. Bayer CropScience has developed a seed treatment that offers dual protection against a range of early season insects like black cutworms, and also delivers powerful protection against a wide variety of nematodes.

For most of the past decade, Poncho seed-applied insecticide was the top-selling product of its kind in corn. Bayer CropScience has now combined Poncho with VOTiVO seed treatment to provide a powerful broad-spectrum solution for corn growers. A revolutionary advance in nematode control, Poncho/VOTiVO includes a bacteria strain that colonizes the root surface of the corn plant and denies multiple nematode species from accessing feeding sites on the root. This living barrier actually grows with the corn, protecting the delicate vascular system of the plant and bringing healthy corn to harvest.

August 27, 2012  By Bayer CropScience


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