Abstract
Eggs of Diabrotica longicornis barberi, the northern corn rootworm, field conditioned by exposure to normal descending fall and winter temperatures, were subjected to 0, −5, −7.5, and −10°C for 7, 14, 21, 35, and 42 days, respectively, in the laboratory. Hatch of eggs occurred in all treatments after incubation at 25°C. It is concluded that eggs of the northern corn rootworm have greater cold hardiness than those of the western corn rootworm, Diabrotica virgifera virgifera LeConte, which had 3.3% hatch after 21 days at -10°C.