The efficacy of mycoinsecticides of Beauveria bassiana against silverleafwhitefly (Homoptera : Aleyrodidae) on poinsettia

摘要

Mycoinsecticide agents may be appealing alternatives to chemical insecticides for silverleaf whitefly Bemisia argentifolii Bellows and Perring, n. Sp. management on poinsettias (Euphorbia pulcherrima willd. ex Koltz) in the greenhouse. The efficacy of two mycoinsecticides containing Beauveria bassiana (Balsamo) Vuillemin were tested against the silverleaf whitefly in greenhouse studies. An oil emulsion and wettable powder formulation of B. bassiana did have a significant, though not acceptable, effect on the silverleaf whitefly. The F-1 nymphal populations were reduced to significantly lower levels (18-36 nymphs per leaf) when an oil emulsion of B. bassiana was applied over a three week period. A wettable powder formulation was applied over a two week period to reduce F-1 nymphal populations to significantly lower levels (21-24 nymphs per leaf). Both of the mycoinsecticide formulations maintained the F-2 nymphal populations at significantly lower levels (16-76 nymphs per leaf). The oil emulsion and wettable powder formulation significantly reduced F-1 (4-11 adults per leaf) and F-2 (3-7 adults per leaf) adult emergence compared with the untreated population. The mycoinsecticides did not appear to have a residual effect, and as a result, the second generation whitefly populations increased to unacceptable levels.