May 2, 2005

Soybean Growers Brace for Insect Outbreak

TOLEDO, Ohio (AP) -- Farmers are bracing for what researchers predict will be the return of an insect that attacks soybeans in the Midwest, where most of the crop is grown.

For now, farmers must decide whether it makes sense to spray for soybean aphids before the insects emerge. Some say they will wait until they know whether their fields have been infested. Others aren't taking chances.

"All of the research points to this being the year for aphids," said Allen Armstrong, who plans on preventive spraying on about a quarter of his soybeans.

Most of the nation's soybeans are grown in Midwest.

The United States dominates in soybean production, accounting for 40 percent of the world market. Exports of soybeans - at $8 billion to $9 billion a year - are worth more than any other crop.

The tiny aphids suck the sap out of soybean plants and stunt their growth, leading to less productive plants. They were a problem two years ago but nearly nonexistent in 2004.

Farmers are faced with yield losses or spending $12 to $15 per acre to buy and apply insecticide once the insect is detected, usually in late July or early August.

Once Armstrong spots any aphids this summer, he plans on spraying all of his fields instead of waiting to see if the numbers increase.

"We'll be a little more proactive," said Armstrong, who lives near South Charleston in western Ohio.

Farmers who opt to spray the insecticide early will be wasting their money, said Kevin Steffey, a crop sciences professor at the University of Illinois.

The early application will be effective for only up to two weeks, he said. "If we have a population explosion, they'll be spraying again."

Jamie Mossbarger, spokeswoman for the Ohio Soybean Council, said she thinks only a small number of producers will spray before they find the aphids.

Steve Miller, a northwest Ohio farmer near Bucyrus, said he will wait for fear the spraying could kill the bugs that eat the aphids.

Entomologists generally expect a large aphids population this summer based on field surveys taken last fall. Traps found a large number of aphids on trees, an indication that they will be back in full force.

Most of the aphids in Ohio will migrate from Minnesota and Wisconsin.

Researchers now think the aphids are on a two-year cycle. But because they have been around during only four growing seasons, it's hard to predict what will happen this year, Steffey said.

"That may sound like a lot of time but quite honestly it isn't," he said. "What we don't know is what the weather is going to be like this summer."

A hot summer could suppress an outbreak, he said.

Farmers should be ready to scout their fields this summer and look for the aphids, said Ron Hammond, an entomologist with the Ohio Agricultural Research and Development Center.

Once there's evidence that the numbers are increasing, then it's best to spray, he said.

Planting early in May also could help limit damage because there's a belief that soybeans planted early in are not as susceptible to aphids.

If you really do a good job of scouting and spraying," Hammond said, "it's not difficult or impossible to control."


On the Net:

Ohio State University Extension: http://extension.osu.edu/

Ohio Soybean Council: http://www.soyohio.org/

University of Illinois: http://www.cropsci.uiuc.edu/general