EATON COUNTY, Mich. — The armyworm infestation is worse than usual this year, but exactly how bad it is may depend on whether a producer is vigilant enough to keep the pest at bay.

“I’ve never seen armyworms as I’ve seen it this year,” said Charles Scovill, an agronomist with Garst Seeds, Inc., a company based in Iowa.

Scovill works with producers in Michigan and Indiana.

“I’ve seen them as far north as Gratiot County. They’re pretty widespread,” Scovill said.

Scovill said that armyworms can devastate a grassy field, including wheat, corn, and soybean that has weeds in it, in a short period of time. Armyworms don’t eat the corn itself, but instead eat the leaves of the plant, making the plant look like a stick. Despite this, the plant can usually survive, Scovill said.

Once a mass of armyworms gets done eating everything in one field, “they will literally march across the road” to the next field it can consume.

According to Scovill, adult moths were flying around three weeks ago, laying eggs. In a matter of weeks after the eggs are laid they hatch, and small worms start making their way through grassy fields. If more than 50 percent of the plants in a field show fresh feeding and the worms are less than 1.5 inches long, then it makes economic sense to spray with insecticide, Scovill said.

Christina Difonzo, an entomologist at Michigan State University, didn’t seem as worried about this year’s infestation.

“It’s worse than it was last year, but people have heard the word, and they’re out there,” Difonzo said. “My impression is it’s not as bad as 2004. That year was pretty bad in wheat, and in corn.”

The key is to do scouting for any sign of feeding damage.

According to Difonzo, a lack of weed control can make the armyworm problem worse.

This farm news was published in the June 28, 2006 issue of Farm World, serving Indiana, Ohio, Illinois, Kentucky, Michigan and Tennessee.