Researchers at Colorado State University, University of Nebraska, and the Agricultural Research Service have developed an innovative way to fight the wheat stem sawfly, a pest that causes $350 million in yearly crop losses. This method relocates beneficial parasitoid wasps by baling wheat straw that naturally contains their larvae and releasing them into infested fields at the proper time. Each bale can deliver thousands of wasps, which then attack the sawfly. This simple, scalable approach gives farmers a new, sustainable tool against a pest that has been nearly uncontrollable for decades.
For over 50 years, little progress has been made in controlling wheat stem sawfly, one of the most damaging pests in the Great Plains. Traditional pesticides are largely ineffective, and resistant wheat varieties offer limited protection. By leveraging natural enemies of the sawfly—parasitoid wasps—this novel biological control method is practical, scalable, and environmentally friendly.
The innovation, lovingly called the Beneficial Bug Baler, captures and relocates large populations of parasitoid wasps (Bracon cephi) directly into wheat fields. The process involves baling wheat straw from fields where parasitoid larvae are present, transporting the bales, and unrolling them at sawfly-infested sites. A key breakthrough is producing low-density straw bales, which significantly improve wasp survival and emergence compared to conventional tightly packed bales.
Field trials demonstrated that a single bale can release 5,000–10,000 parasitoids, with an entire truckload delivering nearly 1 million beneficial insects—an order of magnitude higher than many past biocontrol campaigns. Once released, the wasps establish in new fields and parasitize sawfly larvae, reducing pest populations and limiting crop damage. This scalable approach can be rapidly deployed across wheat-growing regions and adapted to other crops with stem-boring pests.
Available for Exclusive Licensing
TRL: 7
US Provisional Patent
Punya Nachappa
Jeffrey Bradshaw
Peter Kleinman
Tatyana Rand
Erika Peirce
Kyle Mankin
Grace Miner
Jessy McGowan
Jessy.McGowan@colostate.edu
970-491-7100