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Wheat Head Army Worm May Be New Pest for Washington

Graders report some loss of quality.

Recently the Washington state grain graders contacted Davenport Union Warehouse about some of their wheat samples that contained about 2% broken kernels and would only grade "sample".

Initially, it looked as though grain borers or grasshoppers were causing the damage, but Kevin Reed of the McGregor Company in Davenport did some excellent scouting in affected fields and found pupae that are most likely from the wheat head army worm, reports Spokane County Extension Agronomist Diana Roberts.

Washington State University entomologists Dave Bragg and Rich Zack will maintain the pupae until moths emerge so that they can confirm that the insect is as suspected.

If confirmed, this will be the first record of t WHAM causing noticeable damage in Washington, says Roberts, who says the pest has seldom even been found in the state.

Reports from other states indicate that WHAM is a minor grain pest but occasionally causes noticeable crop injury. This is usually detected only at harvest, she says, and may be confused with damage from grain storage insects, as occurred in this situation.

According to Davenport and Odessa Unions in Washington, the infestation is localized and sporadic within an10-mile radius of Davenport. Winter wheat is affected primarily though there is a little evidence of the insect in some spring grains, says Roberts.

The WHAM overwinters in the pupa stage. Adults emerge in the spring and lay eggs on many grass species, but wheat is the preferred host, she adds.

Photos of this pest may be viewed on line at under "What's New".

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