Kansas corn battles rising pest and disease pressure

Crop diseases and pests are taking a toll on Kansas corn. Two crop experts from Kansas State University share tips for producers dealing with cutworms and armyworms.

Kansas’ 6.4 million acres of planted corn are facing several challenges this year.

Disease pressure is taking a toll on the crop. Seven counties in northeast Kansas have reported cases of tar spot. Pests, including armyworms and cutworms, also pose a significant concern.

However, despite these concerns, the latest Crop Progress Report released by the U.S. Department of Agriculture (USDA) rated Kansas corn at 69 percent good to excellent.

Two crop experts from Kansas State University (K-State) weigh in on current conditions in the state.

Dealing with Armyworms

“Right now, the larvae that I’ve seen are relatively large, which means they have almost completed their feeding, so they’re not going to feed and they’re not going to cause much more damage,” said Jeff Whitworth, Associate Professor of Entomology at K-State.

“What you need to do is get out and monitor your yard, your crop, or whatever it is you’re worried about to see what stage they’re in,” Whitworth said. “It’s going to be different for you in a week or two. Egg laying can make a difference as far as how much longer the larvae are actually feeding. If they’re relatively large larvae — by that, I mean, an inch to an inch and a quarter — they’re not going to feed much more. So, that has a big impact on when you want to treat, if you want to treat.”

The K-State expert advises scouting for armyworms at night, as the pest is nocturnal and primarily feeds in the dark.

Dealing with Cutworms

Another corn pest of concern is the Western Bean Cutworm, which is currently active in western Kansas.

“We’ve got a lot of fields tasseling in western Kansas right now, and the Western Bean Cutworm overwinters in the soil as pupa — and about this time of year, adult moths are going to be emerging from the soil — and they’re going to be gravitating towards cornfields,” explains Anthony Zukoff, an K-State Extension Associate specializing in Entimpology.

Zukoff says that during tasseling, females lay eggs in corn fields, with caterpillars migrating to developing ears and consuming kernels, leading to a reduction in yields.

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