Corn rootworms (CRW) are serious pests of corn in the United States. The larvae feed on the roots, which can reduce yield. Producers may soon be able to use Bt corn to control CRW populations. However, resistance among CRW to the Bt toxin could quickly evolve. To diminish resistance evolution, producers will be required to plant a refuge of non-Bt corn. To keep resistance numbers low, sufficient gene flow among CRW populations must occur from the refugia to the Bt fields. Dispersal is a means by which gene flow occurs among populations. We investigated the dispersal of northern and western CRW within cornfields, and between cornfields and soybean fields in the South Dakota Areawide Management site. We placed Pherocon AM sticky traps at different heights between cornfields and soybean fields. Sticky traps were placed horizontally within cornfields above the corn canopy to estimate emigration and immigration. We captured more northern than western CRW, and both were captured at the lowest height between fields. More CRW were captured between continuous (CC) and first year (FY) cornfields than between other combinations of fields. More western CRW were captured flying from soybean to CC than from CC to soybean. We captured more western CRW flying from FY corn to soybean than from soybean to FY corn. More northern CRW emigrated from cornfields than immigrated into the cornfields, but just the opposite for western CRW. Western CRW numbers were low and may not indicate their migratory behavior into and out of cornfields.
Species 1: Coleoptera Chrysomelidae Diabrotica barberi (northern corn rootworm)
Species 2: Coleoptera Chrysomelidae Diabrotica virgifera virgifera (western corn rootworm)
Keywords: Cornfields, Soybean Fields
The ESA 2001 Annual Meeting - 2001: An Entomological Odyssey of ESA