, Farm Journal Livestock and Production Editor
Wheat is hitting Hessian flies hard. Studies by Purdue University and USDA show resistant wheat plants stop Hessian fly larvae by destroying the fly's midgut and its ability to absorb nutrients.
Within three hours of ingesting resistant wheat, the Hessian fly larvae midgut, similar to human intestines, showed abnormal microvilli, fingerlike appendages that extend inward from the walls of the midgut to increase surface area for nutrient absorption. About six hours after the pest had ingested resistant wheat, the microvilli were nearly destroyed.
"Some chemical or compound from the resistant plant is causing the microvilli to be disrupted, and it's happening very quickly,” says Purdue entomologist Richard Shukle. "The midgut is certainly one of the major targets of the defense compounds elicited from a resistant plant.”
There are about a half dozen undeployed genes identified in wheat that offer high resistance to Hessian flies and could be deployed to defend plants. The key is to know which resistance genes to use, researchers say, as the Hessian fly is a flexible pest known to overcome several genes intended to protect wheat lines.