The efficiency of parasitoids wasps for biological control of whiteflies in cucumber greenhouses

A serious pest of agricultural crops are two species of whitefly that (Trialeurodes vaporariorum and Bemisia tabaci), which also make damages to greenhouse crops and ornamental plants. The biocontrol agents for these pests belong to the aphelinid wasps. To date two species of the genus Encarsia and Eretmocerus are used as effective natural enemies worldwide under greenhouses condition to control whiteflies. In this project, these parasitoids were release in a commercial greenhouse (5000 m2) to control the whiteflies populations in Varamin region (east of Tehran). Releasing was either uniform or spotted, in the uniform releasing 3, 6 or 9 parasitoids was considered per square meters, but in spotted releasing, in infection point, releasing rate was increased depending on the whitefly infestation. The results showed that the population of T. vaporariorus was increase from week 9th till week 14th. However, it was decrease from 23th week onward, while the parasitism rate of E. eremicus was higher than E. formosa (more than 80%). Therefore, using of these agents (in biological control program) can control the whiteflies population throughout the season. However, in addition to a good infrastructure of the greenhouses, other biological control agents predator mite) that are released to control other pests, can feed from the whiteflies nymphs, and reduces the pest population.