Susceptibility of Vespula vulgaris (Hymenoptera : Vespidae) to generalist entomopathogenic fungi and their potential for wasp control

The pathogenicity of Vespula vulgaris wasp workers and larvae to a range of fungi was determined. All fungi were isolated in New Zealand and included isolates from Vespula, known generalist insect pathogens, and isolates gene rally nonpathogenic to insects. Workers and larvae were highly susceptible to pathogenic isolates at high spore concentrations (>1.75 x 10(5) cfu/indi vidual). Eight isolates, two of Metarhizium anisopliae, five of Beauveria b assiana, and one of Aspergillus flavus were pathogenic while a single isola te of M. flavouiride var. novazealandicum, Cladosporium sp,, and Paecilomyc es sp. were not. The transfer of spores between workers, and between worker s and larvae, was also investigated using several different application met hods. Transfer of spores occurred between treated and untreated individuals , and for some of the application methods sufficient spores were transferre d to cause mortality of the nontreated individuals. These findings are rela ted to the potential of fungi for the control of wasps, (C) 2000 Academic P ress.