D. Moore

Biological control of Rastrococcus invadens. BNI 25 (1)

Abstract:

Rastrococcus invadens became a serious pest of (especially) mango and citrus in West Africa in the 1980s. Economic losses were high, with mango yields often reduced by 50-90%, and pest infestations also caused social and cultural problems. Surveys for natural enemies were conducted in India and Malaysia, following taxonomic work which identified the likely origin of the pest. Work in India resulted in the provision of two primary encyrtid parasitoids, Gyranusoidea tebygi and Anagyrus mangicola. Gyranusoidea tebygi was released in Togo in 1987-88, rapidly controlled the mealybug in most areas, and spread at around 100 km/year. Anagyrus mangicola was introduced after laboratory studies indicated that it was unlikely to reduce control by G. tebygi and was likely to supplement it in certain situations. Both parasitoids were subjected to high levels of indigenous hyperparasitism, which did not interfere markedly with the control exerted. The mealybug remains under good control; the benefits to African farmers amount to many multiples of research and implementation costs and the project also resulted in the amelioration of many social problems caused by the mealybugs.