PREDICTIVE MODELING IN BIOLOGICAL-CONTROL - THE MANGO MEALY BUG (RASTROCOCCUS-INVADENS) AND ITS PARASITOIDS

(1) A mealy bug (Rastrococcus invadens) has recently become an important pest of mango and citrus in West Africa. Two parasitoids collected in India have been considered as biological control agents. (2) We develop age-structured host/parasitoid population models with overlapping generations to investigate the interactions of the host and its two potential parasitoids. (3) The models predict that one parasitoid (Gyranusoidea tebygi) will lead to a greater decrease in host density than the other parasitoid (Anagyrus sp.). We test the robustness of this prediction by sensitivity analysis. (4) The models predict that the addition of Anagyrus sp. to a system already containing G.tebygi will lead to little improvement in host depression. (5) We argue that models of intermediate complexity may offer the best prospects of predictive biological control in situations where it is not practicable to obtain the information needed to build and parameterise a large, tactical simulation model.