Fourth International Bemisia Workshop International Whitefly Genomics Workshop
Interaction between Two Entomopathogenic Fungi with the Parasitoid Encarsia formosa Gahan in the Greenhouse Whitefly Control
1 Programa en Entomología, Campus Montecillo, Colegio de Postgraduados, Montecillo Estado de México, México. Correspondence: ladeorar@colpos.mx
2 Sanidad Vegetal, SAGARPA, Celaya, Guanajuato, México
Interaction of the entomogenous fungi Paecilomyces fumosoroseus and Beauveria bassiana with the parasitoid Encarsia formosa, all natural enemies of whiteflies, was studied under greenhouse conditions. Second instar nymphs of the whitefly Trialeurodes vaporariorum were treated with the entomopathogens and later exposed to parasitoid females at different intervals of time. With the combination P. fumosoroseus-E. formosa nymphl mortality decreased with increases in time between application of the fungus and the release of the parasitoids (66.9% to 49.3%, 3 days later). In contrast, the combination B. bassiana - E. formosa showed that mortality increased as the time interval increased (52.6% to 61.9%, 3 days later). In both cases, mortality from the effect of the two control agents was greater than that caused by either of the natural enemies acting independently. In a second experiment, each fungus was applied to whitefly nymphs previously exposed to E. formosa. The greatest mortality was observed when fungi were applied 2 days after nymphs were exposed to the action of the parasitoids (75.4% in the combination E. formosa - P. fumosoroseus, and 84.5% in the combination E. formosa - B. bassiana). Mortality decreased as the time between parasite exposure and infection increased. The results suggest that the combination of E. formosa and one of the two entomopathogenic fungi has potential use in the control of T. vaporariorum nymphs under greenhouse conditions.