Spring wheat pest attacks kernels
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Orange blossom wheat midges have nothing to do with weddings and everything to do with destroying a spring wheat crop.
The little insects are about half the size of a mosquito and neon orange. Midges lay their eggs in the wheat flower. When the larvae hatch in about a week, they eat the wheat kernels.
A farmer can’t tell by looking at the crop if it’s infected or not because the larvae feed inside the wheat heads, and that’s where traps come in — to let growers know if they have the pests before harvest time.
Jack Stivers, Montana State University Extension Agent for Lake County, has 15 traps around Lake County to catch the tiny bugs.
Stivers’ traps look like a triangle, a small A-frame shape about a foot long, with a sticky floor and an attached container of pheromone. They used to be white, but now producers are advised to paint them green. White attracts other insects, too, while the green paint is most come-hither for the midges.
The northern part of the county has a larger midge population than the south, Stivers said. For example, in Moiese there were none where he checked.
Midges are small and fragile. They lay eggs in the evening from about 8:30 to 11 p.m. when the humidity rises. Females won’t lay eggs when the weather is cold, below 59 degrees, or the wind is blowing, according to an MSU self-learning flyer.
Growers who want to check for midges can call Stivers to come out and trap the orange insects and do some monitoring or go look in the field.
“When you go scouting, go at about 8:30 p.m.” Stivers said. “Leave the dog in the pickup. Let everything calm down. Then walk into the field and watch for swarms.”
If growers don’t call Stivers to set one of his traps or monitor the field, they can use a white, or maybe a green, paper plate coated with cooking spray, such as Pam, and see if they can catch any midges in a swarm.
“If there are six midges per head, you need to spray,” Stivers explained.
The pesticides most used to kill the midges are Warrior II or Lorsban, according to Stivers.
Scott Johnson, seed plant manager at Westland Seed, said Warrior II is a restricted product; growers need to have a pesticide applicator’s license from the Department of Agriculture to use it. Growers can hire someone with a license to apply the insecticide.
“What we do for our growers or our customers is to monitor wheat midge activity, scout in the evenings, identify the problem and provide a solution,” Johnson said, since Westland Seed has an applicator’s license.
If orange blossom wheat midges are not eradicated, the little orange buggers will burrow into the ground. If the weather’s too dry, the larvae can remain dormant for at least five years, with some studies claiming 13 years — so even a drought won’t get rid of them.
To find out more about wheat midges, contact the MSU Extension Office at 406-676-4271.
