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Thermal death kinetics of Conogethes punctiferalis (Guene´e) (Lepidoptera: Pyralidae) at different life stages, heating rate, and temperature is essential for developing postharvest treatments to control pests in chestnuts. Using a heating block system (HBS), the most heat-tolerant life stage of C. punctiferalis and the effects of heating rate (0.1, 0.5, 1, 5, and 10C/min) on insect mortality were determined. The thermal death kinetic data of fifth-instar C. punctiferalis were obtained at temperatures between 44 and 50C at a heating rate of 5C/min. The results showed that the relative heat tolerance of C. punctiferalis was found to be fifth instars>pupae> third instars> eggs. To avoid the enhanced thermal
tolerance of C. punctiferalis at low heating rates (0.1 or 0.5C/min), a high heating rate of 5C/min was selected to simulate the fast radio frequency heating in chestnuts and further determine the thermal death kinetic data. Thermal death curves of C. punctiferalis followed a 0th-order kinetic reaction model.
The minimum exposure time to achieve 100% mortality was 55, 12, 6, and 3 min at 44, 46, 48, and 50C, respectively. The activation energy for controlling C. unctiferalis was 482.15 kJ/mol with the z value of 4.09C obtained from the thermal death–time curve. The information provided by thermal death kinetics
for C. punctiferalis is useful in developing effective postharvest thermal treatment protocols for disinfesting chestnuts
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