MORTALITY OF MATURE THIRD-INSTAR CARIBBEAN FRUIT FLY (DIPTERA: TEPHRITIDAE) EXPOSED TO MICROWAVE ENERGY

Our investigation estimates time–temperature relationships and demonstrates the effect of rapid heating on mortality of Caribbean fruit fly, Anastrepha suspensa (Loew). Mature larvae (third instars) in water were exposed to each of seven temperatures (44, 45, 46, 47, 48, 49, and 50 °C) and each of five power levels (11, 27.5, 55, 88, and 122 W) in a research-quality microwave oven. Controls were immersed in water for 30 min and not exposed to microwave energy. Data were analyzed by a probit model with three explanatory variables. The variables were time to reach target temperature, power, and final temperature. Temperature needed to control the larvae increased as power increased. Of the power–temperature levels, the only combinations that resulted in > 99% mortality were the lowest power (16 W) at 49 or 50 °C and 30 W at 50 °C. Time required for > 99% mortality decreased with increased power. Thus, as power delivered to larvae increased and time needed to reach exposure temperature deceased, percent mortality decreased. We conclude that rapid heating imposes serious constraints on the use of heat-induced mortality; this result raises important questions that must be addressed because quarantine security may be jeopardized.