Potential of single and combined releases of Eretmocerus mundus and Macrolophus melanotoma to suppress Bemisia tabaci in protected eggplant

The parasitoid Eretmocerus mundus Mercet (Hymenoptera: Aphelinidae) and the predator Macrolophus melanotoma (Costa) (Hemiptera: Miridae) are two important natural enemies of Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) which are distributed throughout the Mediterranean region. Both natural enemies are used in the biological control of B. tabaci. In this study, the success of single and combined release of Er. mundus and M. melanotoma against B. tabaci on eggplant was determined in 3 × 3 × 2.5 m net cages established in a greenhouse during the period of 2009 and 2010. Four different experiments were conducted; Er. mundus single release, M. melanotoma single release, Er. mundus + M. melanotoma combined release, and B. tabaci single release (control). For the evaluation of population development of whitefly and the parasitoid, leaf samples were taken at five day intervals. In addition, numbers of the predatory insects were calculated by using visual control method on whole parts of 15 plants in different treatments. Results of this study showed that the number of whiteflies was the highest in the control treatment, followed by the M. melanotoma (single), Er. mundus (single) and Er. mundus + M. melanotoma (combined) treatments, in both years. Low B. tabaci populations were observed in combined release treatments and the weekly mean density of immature whiteflies never exceeded 3.99 per cm2 leaf area. M. melanotoma was not successful against B. tabaci when released alone. However, it does contribute to the success of biological control of B. tabaci when released with Er. mundus. In light of these results, we suggest the combined release of Er. mundus and M. melanotoma for effective control of whitefly in greenhouse grown eggplants.