Northern corn rootworm (Coleoptera: Chrysomelidae) temperature requirements for egg development

Temperature-dependent development of laboratory-wintered eggs of northern corn rootworm, Diabrotica barberi Smith & Lawrence, was described using data from constant temperature laboratory experiments. Median development of postdiapause eggs at constant temperatures of 15, 18, 20, 23, 25, 27, and 30 degrees C required 59, 30, 24, 17, 15.5, 14, and 14 d, respectively. Linear and nonlinear models were fitted to temperature versus developmental rate data. Variation in developmental rates across temperatures was modeled with a cumulative Weibull distribution. Mean developmental rate was linear between 15 and 27 degrees C, optimal at 27 degrees C, and decreased at 30 degrees C. The thermal threshold for development (10.9 degrees C) was determined by extrapolation with median egg hatch occurring after 238 DD (10.9).