Identification of potential areas of establishment of the parasitoid Diachasmimorpha longicaudata (Hymenoptera: Braconidae) to guide it releases for biological control of Bactrocera dorsalis (Diptera: Tephritidae)

The Opiine endoparastoid Diachasmimorpha longicaudata (Ashmead) (Hymenoptera: Braconidae) is one of the parasitoid credited with outstanding success of biological control of tephritid fruit flies. The invasion and spread of Bactrocera dorsalis in Africa have led to massive economic losses due to direct damage to fruits including quarantine restriction. Biological control using parasitoid has high potential in reducing the pest population when used within the context of IPM approach. The aim of this study was to determine suitable areas for potential establishment of D. longicaudata using Insect life cycle modeling (ILCYM) to guide its field releases in Africa. To address this, we have calculated the thermal requirement of the parasitoid and simulated parameters such as population growth at different temperature requirements, suitable areas for establishment and number of generations per year under projected climatic conditions. The lower thermal threshold for the development was estimated at 10.0°C, with a thermal constant of 333.3-degree days. Maximum temperature threshold was estimated at 33.7°C. Fecundity was highest at 25°C, with 177.3 eggs/female. Population growth parameters was affected by temperature. The findings of this study showed that D. longicaudata could successfully establish in tropical and sub-tropical regions of Africa under both current and future climatic scenario. However, a slight change in the suitable areas is expected by the year 2050 due to slight and gradual rise in temperature. The outcome of this study provides vital information to guide release of this parasitoid in Africa for classical biocontrol of B. dorsalis.