Archive for Wednesday, June 27, 2007

Army worms taking a bite out of wheat crops

June 27, 2007


John Werth, of Werth Aerial Spraying, examines a field of wheat for the presence of the wheat head army worm in a field near Schoenchen.

John Werth, of Werth Aerial Spraying, examines a field of wheat for the presence of the wheat head army worm in a field near Schoenchen.

— It just wasn't enough, the freezing temperatures, leaf and stripe rust and then hail.

Wheat head army worms attack a head of winter wheat.

Wheat head army worms attack a head of winter wheat.

No, Mother Nature - or someone equally wicked - had to toss in an abundant supply of wheat head army worms - not your everyday wheat pest.

And with harvest fast approaching, the damage already caused by hail storms and rust, there's little anyone can do but wait and hope for the best.

The worms are hungry little critters, feeding at night or during the cool of the day, hanging from awns and feasting on kernels of ripening wheat.

John Werth had planned on taking to the air on a recent morning to spray at least one field of wheat that has an active infestation of the worms. But an in-depth check of that field a few days later showed it probably wasn't a good idea.

That's because the hail damage, the rust damage and the field's fast-approaching date with a combine all made Werth change his mind.

"It's not even feasible to spray it," he said.

Spraying for the worms requires a two-week interval until harvest. Many of the fields in the Schoenchen area where Werth lives, farms and pilots his crop-duster will be ready for cutting within less than 10 days.

"We're behind on this just like the rust," he said, referring to an earlier situation where farmers were being urged to spray for leaf rust. But it simply was too late to do any good.

Cost also is a consideration in deciding if farmers should spray.

With rust, the cost was higher. But for the worms, the cost would be anywhere from $10 to $11 an acre - a couple bushels of wheat at today's prices.

While there are differing opinions whether it's worth it to spray, perhaps the biggest danger is the penalty that could be applied to farmers when they deliver the grain to the elevator at harvest time.

That's because the damage can't be differentiated from "insect-damaged grain" when it is graded for delivery to elevators and the baking industry. IDK, as it is called, can result in some fairly stiff penalties on the entire truckload of wheat brought in to an elevator.

Werth had been looking at wheat fields throughout the area, and his phone was ringing off the wall.

"I only took one step in here, and I saw this," he said at a field near his home.

"There's one, two, three, four, five, without having to do much," he said pointing to worms on the wheat heads and scattered about on the ground at the base of the plants.

Werth was hoping to have a small window of opportunity to do some spraying to halt the damage caused by the worms.

"I don't think we'll be able to get in a field for a week," he said. "If it rains again, it might be two weeks.

"In a few days, they can do a lot of damage. When you have hail, it's hard to make a decision."

For entomologist J.P. Michaud, there's no question farmers can't justify the expense of spraying. The interval between spraying and harvest also is hard to overcome, he said.

He's been taking a close look at the worms to update entomology information at Kansas State University. But there's still plenty that is not known, such as its migration pattern.

Michaud said the worms hang upside down and munch away on the kernels of wheat.

"They grind the wheat like it's in a grinder, and then they chew it," he said. Color varies depending on the maturity of the wheat they are eating.


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