Wheat's genetic resistance to Hessian flies has been failing, but a group of Purdue University and U.S. Department of Agriculture scientists believe that other plants may soon be able to come to the rescue.

The Purdue and USDA research team developed a method to test toxins from other plants on Hessian fly larvae. The test simulates the effect of a transgenic plant without the lengthy and costly procedures necessary to actually create those plants.

"For years, people have tried to develop a bioassay, but that hadn't happened until now," said Richard Shukle, a research scientist with the USDA Agricultural Research Service Crop Production and Pest Control Research Unit working in Purdue Entomology, whose findings were published in the Journal of Insect Physiology.

Shukle said the 33 genes known to give wheat resistance to Hessian fly attacks have been failing, causing scientists to develop methods to stack those genes together as a defense. But another solution could include adding other plants' toxins to wheat to bolster its defenses.

The problem has been with the unique way in which Hessian fly larvae attack and feed off wheat. The larvae secrete a substance onto the plants that creates a sort of wound on the plant tissue, opening it up for the larvae to feed on.

Toxins can be tested on other pests by adding those toxins to a plant-based artificial diet and feeding them to the insects. But Hessian fly larvae won't take the bait, meaning that until now the only way to test poisons from other plants was to create lines of transgenic wheat and feed them to the flies.