Effects of heat treatments on mortality of different life stages of the cowpea weevil., Callosobruchus maculatus Pic. (Col., Bruchidae)

Cowpea weevil, Callosobruchus maculatus (Pic.), is one of the important pests of food industry in the world wide. The use of high temperatures or heat treatments is a very effective method for managing of the pests of stored products. In this study, the mortality of the pest in 5 constant temperatures, including 45, 50, 55 and 60°C each at durations of 5, 10, 15, 20 and 30 minutes on different growth stages (egg, 1-days larvae, 11-days larvae, pupae and adult C. maculates) was determined. The treated insects, were kept at 30±1°C and relative humidity of 65±5%. the results showed that, The most sensitive and resistant stages were eggs and pupal stages, respectively. It also revealed that the minimum temperature to control eggs, 1-days larvae, 11-days larvae, pupal and adult stages were, 50, 50, 55, 55 and 55°C respectively. Since all stage of the insect are usually present in stored products, it is recommend to use 55°C heating at the duration of 15 minutes to control stored products infested with C. maculates.