Biological control of bemisia tabaci (homoptera, aleyrodidae) in protected tomato and pepper culture in southern Spain

Abstract

The whitefly Bemisia tabaci Gennadius biotype “Q” is an efficient vector of tomato yellow leafcurl virus (TYLCV), the principal cause of damage in tomato, and also causes direct injury to pepper. Management of this pest in protected culture of these crops in southern Spain has relied primarily on chemical control. aHowever, overlapping crop cycles, insecticide resistance and public pressure have spurred development of alternative management tactics more compatible environment for biological control such as insect netting for pest exclusion, and, in tomato, TYLCV-tolerant cultivars. Nevertheless, there is minimal information on the feasibility of biological control in the commercial tomato and pepper production systems of this region. In pepper, control of B. tabaci using augmentative releases of two parasitoids, E. mundus and E. eremicus alone and in combination (3 treatments) was compared in 12 commercial greenhouses (4 replicates) in Campo de Cartagena. In tomato, a biologically based integrated pest management (IPM) system was evaluated in 12 greenhouses throughout the production area compared with 7 greenhouses utilizing only chemical control. Parasitism rates in pepper were greater and whitefly populations were lower in greenhouses where E. mundus was released alone or with E. eremicus in a 1:1 mixture as compared to E. eremicus alone confirming the value of augmentation with E. mundus. In tomato, incidence of parasitized whiteflies in IPM greenhouses where both parasitoids were released averaged around 50%, with E. mundus predominating, compared to less than 3% parasitism in conventional greenhouses. Insecticide use was lowest and biological control most effective where TYLCV-resistant cultivars and exclusion strategies (insect netting) were used to reduce whitefly populations and the risk of virus disease. The effectiveness of E. mundus and increasing use of compatible control tactics should lead to greater implementation of biologically based pest management in protected tomato and pepper culture.