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.

Related Stories
RFD-TV Markets Expert Tony St. James breaks down the state of agribusiness and harvest progress across each region of the United States for the week of Monday, September 22, 2025.
Ethanol producers face a widening opportunity window as aviation and marine fuel markets expand, with the potential to add billions in demand if policy and certification align.
Lawmakers and ag industry groups welcomed the confirmations, citing the direct impact of these leaders on western ranchers, water and land management, conservation programs, and regulatory reform.
More than 100 pork producers traveled to Washington to meet with lawmakers and underscore the threat to small family farms.
Corn and beef exports showed strong momentum, cotton sales surged, and soybean sales held steady, though China remains absent from the U.S. market.
Cheaper freight is helping exports move, especially corn, but weaker soybean demand looms large.

LATEST STORIES BY THIS AUTHOR:

Cattle groups say additional imports would offer little relief for consumers but could erode rancher confidence as the industry begins to rebuild herds.
Harvest Pace, Logistics, and Input Costs Drive Fall Decisions
The USDA’s latest Hogs and Pigs Report caught some analysts off guard. Inventories came in lower than expected, signaling tighter supplies ahead, even as producers return to profitability this year.
Over the past decade, Tractor Supply has expanded its support through sponsorships and youth programs, all part of its broader mission to invest in the future of agriculture.
Understanding how these tax provisions interact will be key for farmers planning long-term equipment purchases or transfers within the family.
Lyndsey Smith with Real Ag Radio joined RFD-TV to share a Canadian perspective on the discussions.
Agriculture Shows
Special 3-part series tells the story of the Claas family’s legacy, which changed agriculture forever.
From soil to harvest. Top Crop is an all-new series about four of the best farmers in the world—Dan Luepkes, of Oregan, Illinois; Cory Atley, of Cedarville, Ohio; Shelby Fite, of Jackson Center, Ohio; Russell Hedrick, of Hickory, North Carolina—reveals what it takes for them to make a profitable crop. It all starts with good soil, patience, and a strong planter setup.
Champions of Rural America is a half-hour dive into the legislative priorities for Rural America. Join us as we interview members of the Congressional Western Caucus to learn about efforts in Washington to preserve agriculture and tackles the most important topics in the ag industry on Champions of Rural America!
Featuring members of Congress, federal and state officials, ag and food leaders, farmers, and roundtable panelists for debates and discussions.