Abstract:  Fruit fly is one of the most serious quarantine pests. In recent years, Bactrocera dorsalis Hendel (oriental fruit fly), B. papayae Drew & Hancock (papaya fruit fly) and B. correcta (Bezzi) (guava fruit fly) were intercepted frequently in the port of entry. In this study, we detected and compared the heat tolerance of eggs, the 1st instar and 3rd instar larvae of the three fruit flies at temperatures ranging from 44℃ to 47℃ using a hot water immersion technique. The species with the highest heat tolerance were determined through thermal death kinetic model and activity energy. The results showed that there was a positive relation between the mortalities of eggs, the 1st and 3rd instar larvae of all the three species and the exposure time at the experimental temperature. The 0.5 order kinetic model fitted best to predict the LT_99.9968 lethal time at all the treatment temperatures. The order of heat tolerance stage for all the three species was egg>1st instar larva>3rd instar larva. The thermal death time (TDT) curves showed that the egg of B. correcta had the highest heat-resistance among all life stages of three species. This study provides an experimental basis for the development of heat quarantine treatment indicators of fruit flies.

Key words: Bactrocera dorsalis, Bactrocera papayae, Bactrocera correcta, heat tolerance, thermal death time (TDT), thermal kinetics