Bean pod mottle virus can hurt soybean yields, quality and producers' profits.

There's no cure so University of Nebraska researchers are researching prevention strategies. Research by Plant Pathologist Loren Giesler and Entomologist Tom Hunt is laying scientific groundwork for specific management recommendations, which they hope to develop within two years.

The virus, first spotted in Nebraska in 1981, mottles or discolors soybean seeds and leaves. It's spread by spring populations of the bean leaf beetle. It reduces seed size, yield and protein content, which can reduce the price farmers earn for their crop. The team's 2000 survey of 200 Nebraska fields revealed 69 percent had the virus.

The virus is most harmful when young soybeans are infected, but it can show up at any stage, Giesler said. In other states, early infection has caused yield losses exceeding 50 percent.

"In many cases, yield reduction may be absorbing our producers' profits," he said.

Hunt concentrates on the beetle. He and Giesler have found that applying insecticidal seed coatings, which protect seedling soybeans against the beetles, and delaying planting are effective strategies to reduce or limit spring populations of beetles in soybeans.

Giesler and IANR Soybean Breeder George Graef evaluate soybean breeding lines for virus susceptibility and resistance.

Giesler has found varied responses to the virus but no resistance. He's also examining how the virus affects seed quality and yield. Giesler and plant pathology colleagues are working on a test to quickly differentiate virus strains. This will allow the team to determine variation in aggressiveness among strains that has been observed elsewhere.

This research is part of a larger regional study. The Nebraska Soybean Board, North Central Soybean Research Program, the Layman Fund and industry grants help fund this work.

– Sandi S. Alswager

IANR Entomologist Tom Hunt (left) and Plant Pathologist Loren Giesler inspect soybean pods for bean pod mosaic virus.

The virus discolors soybean seeds and reduces yields and bean quality.