Straw Bale Delivery System Tackles Devastating Wheat Pest
Wheat farmers in the Great Plains region of the US have found an innovative way to tackle the devastating wheat stem sawfly pest, which costs them $350 million annually. Researchers from the Agricultural Research Service (ARS) and their university colleagues have successfully tested a method using baled wheat straw as a delivery system for Bracon parasitoids, the natural enemies of the sawfly.
The technique involves harvesting and transporting straw bales to areas where wheat stem sawflies are present. The parasitoids emerge from the straw and begin searching for their prey, potentially reducing sawfly populations and saving farmers millions in losses.
According to a 2025 study published in Arthropod Management Tests, nine straw bales produced around 67,500 Bracon parasitoids at the ARS field station. The researchers found that these parasitoids can travel up to 50 meters into fields and attack sawflies, with evidence of parasitism observed even beyond the immediate release area.