LOW-TEMPERATURE EFFECTS ON HATCH OF WESTERN CORN-ROOTWORM EGGS (COLEOPTERA, CHRYSOMELIDAE)

This study determined the rate of mortality in western corn rootworm e ggs exposed to different low temperatures for up to 14 weeks. Eggs fro m a laboratory colony of the western corn rootworm were placed in the field in August to experience the same soil temperatures as feral eggs . In November they were brought into the laboratory and subjected to t emperatures of 0, - 5, or - 7.5-degrees-C for specific durations. Perc ent egg hatch declined as temperature decreased and duration at reduce d temperature increased. This relationship was described by the equati on HATCH = 81.017 + 2.744.TP + 1.078.TP. TM (r2 = 0.823), where TP and TM denote exposure temperature and temperature duration, respectively .