Scientists unravel corn pest’s overwintering genes
Western and northern corn rootworms cost U.S. growers more than $1 billion each season. The larvae chew roots that anchor and feed corn plants, knocking down stalks and trimming grain weight. The beetles have become resistant to pesticide rotations and other control tactics, while the eggs they lay in soybean fields lie dormant until corn returns the following spring.
At the heart of that resilience sits diapause, a months-long halt in development that lets corn rootworm embryos ride out freezing soil until seedlings appear. The pause rewires metabolism and boosts cold tolerance. Unlocking the genes governing those shifts offers one of the few remaining levers that could break the pest’s tight synchrony with the crop.
University of Kentucky entomologists tracked gene activity across the full diapause cycle. They collected eggs of both rootworm species—from freshly laid to pre-hatch—and sequenced their messenger RNA profiles to see when stress-response proteins rise, energy pathways dim and developmental hormones stall.
Support from USDA-NIFA and the NSF-backed Center for Arthropod Management Technologies enabled parallel trials that fed adult beetles double-stranded RNA aimed at candidate genes. Lab tests showed the molecules moved from female to egg, giving researchers a gateway for silencing diapause regulators without genetically engineering the crop itself.
The study pinpointed signals that flip the “pause” switch, along with heat-shock and antifreeze proteins that keep embryos viable at sub-zero temperatures.
Knockdown of two top-ranked rootworm genes cut their egg winter survival by up to 70% under simulated field conditions. The team is now raising colonies that skip diapause entirely, trimming experimental cycles from nine months to roughly 10 weeks and accelerating screening of both chemical and RNA-based controls. Thanks to its targeted approach, this research paves the way for corn production that is both profitable and gentler on surrounding ecosystems.
University of Kentucky Agricultural Experiment Station | Project supported by Hatch Multistate capacity funds.
