Predicting Agrilus anxius Gory (Coleoptera: Buprestidae) Adult Emergence by Heat Unit Accumulation

Adult emergence of bronze birch borer, Agrilus anxius Gory, was monitored from 1981 through 1983 in Columbus and Wooster, Ohio. In both locations, emergence began in late May or early June and ended by early July. The best linear regression models for predicting 10% adult emergence were a base temperature of 8°C and a 1 May starting date for Columbus, and a base temperature of 10°C and 1 April starting date for Wooster. A mean degree-day summation model was an even more precise predictor of beetle emergence. Both prediction methods should be more reliable for targeting dates to apply sprays than calendar dates.