Heat, Dryness Take Toll On Soybean Crop

Iowa Farm Scene

End of summer drought conditions have reduced Iowa's soybean yield potential, as well as corn.

Published on: September 9, 2013

"We were blessed with 3 inches of rain the first part of August here in Mitchell County," says Fredericks. "So we are now sitting with a pretty healthy bean crop. We've been inundated with soybean aphids this year. Most farmers growing soybeans in this area sprayed insecticide in August to control aphids."

"Our crop is still healthy and we have moisture in early September," he says. "The balance of the state of Iowa is in reverse. The crop is drying up, beans are running out of moisture and a lot of corn and beans are being pushed faster toward maturity by the heat and dryness. Farmers in the driest areas of Iowa are concerned about lack of yield due to dry weather. But our concern in northern Iowa has to do with late planting. We're worried about an early frost potentially coming along before the beans are mature."

Concern about bean yield potential in Iowa this fall varies significantly across the state

So we're seeing concerns about yields from both ends of the spectrum for very different reasons, he notes. A farmer in Wright County in north-central Iowa says there was a lot of spraying for aphids in August. Was aphid spraying statewide this summer or isolated in various spots in the state? "It was isolated, mostly in northern Iowa," says Fredericks.

He adds, "We're seeing this pest in north-central and northeast Iowa, and the aphid infestations were worth the time and effort to spray. My crop consultant says this year is the most rapid growth in an aphid population he's seen in his career. It was only two or three days, but aphid populations just exploded in the Mitchell County area."

Soybean aphids, along with recent hot, dry weather, have been a challenge for some Iowa growers in 2013

"We were on top of the aphid problem, with a timely spraying of insecticide," says Fredericks. "But the plants were loaded with aphids. Talking with other ISA directors from around the state, aphid populations haven't been a concern for most of them. But aphids were a problem in some northern Iowa fields this year."

It'll be very interesting to see how this year's Iowa bean crop plays out. A lot will depend on the first killing frost, when it comes. The normal date for the first killing frost in Fredericks' area of Iowa usually occurs at the end of September, the last few days of the month.