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Farmers need to check wheat, canola fields for insect damage

Two Oklahoma State University Extension specialists are encouraging wheat and canola growers to climb out of their pickup trucks and walk around in their fields.

Talk about shutting down "windshield farmers." Bob Hunger, OSU plant pathologist, and Tom Royer, OSU entomologist, say producers need to be checking for the presence of both disease and insects in their winter crops.

Hunger, along with his graduate students, recently checked fields near Chickasha and Apache, where they found traces of leaf rust near Chickasha and some evidence of powdery mildew, particularly near Apache.

"What we have seen is in only trace amounts," Hunger said.

He said there are places in Kiowa County where severe tan spot has been seen in wheat fields. He has seen fields near Ponca City where there is a need to apply a fungicide to control the pests. Leaf spot foliar diseases are more severe in no-till fields where wheat residue has been retained on the soil surface, he said.

Leaf spots on lower leaves of the wheat plant can be severe. Hunger believes leaf spot will continue to move up the plants' foliage as long as moisture and temperatures are favorable.

"If infection is severe on the lower leaves of these plants, spraying with a fungicide early in the season would be good," he said. "I would go with the lesser expensive generic fungicides to limit the spread of these leaf spot diseases to older foliage." 

For additional information on early-season foliar wheat diseases and possible control with an early fungicide application, growers can go to the wheat.okstate.edu website, he said.

On the insect side of Southwest Oklahoma small-grain production, "Army cutworms overwinter in Oklahoma," Royer said.

"They tolerate cold temperatures and feed throughout the winter months," he said. "Adult army cutworms migrate to Oklahoma each fall from their summer residence in the Rocky Mountains. They usually seek bare or sparsely vegetated fields (like a newly prepared field ready for sowing wheat or a field where wheat has been 'dusted in' but hasn't yet emerged).

"Just because army cutworm moths prefer to deposit eggs in bare soil, it doesn't mean no-till fields with residue are safe from infestations. So we suggest all wheat fields need to be scouted." 

Royer said moths lay eggs from August through October and the eggs hatch soon after being deposited. That explains why a producer often sees different sizes of larvae in a field. Army cutworms feed throughout the winter and molt several times before they turn into pupae in the soil. Most larvae will be gone by late March.

"Adult moths begin emerging in April and fly back to the Rocky Mountains to spend the summer," he said.

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