Augmentative biological control of Bemisia tabaci biotype 'Q' in Spanish greenhouse pepper production using Eretmocerus spp.

Eretmocerus mundus Mercet is indigenous to the Mediterranean basin and the most abundant parasitoid attacking Bemisia tabaci Gennadius on the southern coast of Spain. However, E mundus was not available commercially until 2002 and the North American Eretmocerus eremicus Rose and Zolnerowich had been used instead to control whiteflies in greenhouse vegetables, including sweet pepper in Campo de Cartagena (Murcia). The ability of these two Eretmocerus species to control R tabaci on pepper by augmentation was compared with weekly releases of E mundus and E eremicus, alone, and in 1: 1 combination (three treatments) initiated early in the winter crop cycle in 12 commercial greenhouses. E mundus rapidly displaced E eremicus in greenhouses where both were released, and eventually, even where only E eremicus was released, indicating that a significant portion of the E mundus population entered the greenhouses from outside. Nevertheless, parasitism rates were greater in greenhouses where E mundus was released, especially early in the trial. Whitefly populations were lower compared to where E eremicus was released alone, presumably in response to parasitism. Thus, higher incidence of parasitism and superior control of B. tabaci with E mundus confirmed the value of early season augmentation with this parasitoid as opposed to E eremicus under conditions of this test. (c) 2005 Elsevier Ltd. All rights reserved.