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Plant Wheat After the Fly-Free Date

This article was originally published on October 15, 2009 and expired on November 1, 2009. It is provided here for archival purposes and may contain dated information.

Hessian fly is a small insect pest of seedling wheat. Adult Hessian flies lay eggs that hatch into maggots that feed at the base and crowns of seedling wheat plants. This results in stunting, lodging and potential plant death.

Traditionally, there have been two methods of controlling Hessian fly in wheat, explains Robert Bellm, University of Illinois Extension crop systems educator. The first method is to delay planting until after a specific calendar date for your area; the second is planting a wheat variety that is resistant to Hessian fly.

Unfortunately, the Hessian fly has adapted to the use of resistant wheat varieties, and the most prevalent biotype of this insect pest is no longer controlled by the resistant varieties currently on the market. This leaves planting after the fly-free date as the only effective method of controlling Hessian fly. Since the Hessian fly has a very short adult life span, waiting until after the fly-free date insures that the adults will die before new wheat is present to lay eggs in. A second key point in this management strategy is to destroy all volunteer wheat during late summer so that there are no alternate egg-laying sites available.

"Delaying planting until after the fly-free date also minimizes the potential for wheat diseases that may be more of a problem than Hessian fly," says Bellm. "These diseases include wheat streak mosaic virus, barley yellow dwarf virus, soil-borne mosaic virus, septoria leaf spot and rust."

The fly-free date begins as early as September 17 in northern Illinois, and as late as October 12 in the southernmost counties of the state. The exact date for your location can be found in the Illinois Agronomy Handbook, available at any county U of I Extension office.

Source: Robert Bellm, Extension Educator, Commercial Agriculture, rcbellm@illinois.edu

Pull date: November 1, 2009

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