ABSTRACT

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 F₁ nymphal populations were reduced to significantly lower levels (18\N36 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 F₁ nymphal populations to significantly lower levels (21\N24 nymphs per leaf). Both of the mycoinsecticide formulations maintained the F₂ nymphal populations at significantly lower levels (16\N76 nymphs per leaf). The oil emulsion and wettable powder formulation significantly reduced F₁ (4\M11 adults per leaf) and F₂ (3\N7 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.

Bemisia argentifolii, silverleaf whitefly, Homoptera, Aleyrodidae, biological control, greenhouse ornamentals, microbials, entomopathogenic fungi

¹Accepted for publication 28 May 1999.
²Department of Entomology, Georgia Experiment Station, The University of Georgia, Griffin, Georgia 30223.