Submitted to: Society for Invertebrate Pathology Annual Meeting Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: August 15, 2003
Publication Date: August 15, 2003
Citation: FILOTAS, M., WRAIGHT, S.P., SANDERSON, J. EVALUATION OF ENTOMOPATHOGENIC FUNGI FOR MICROBIAL CONTROL OF THE GREENHOUSE PESTS MYZUS PERSICAE AND APHIS GOSSYPII. PROCEEDINGS OF THE ANNUAL MEETING OF THE SOCIETY FOR INVERTEBRATE PATHOLOGY. 2003. v. 36. p. 103.
The green peach aphid, Myzus persicae, and the melon aphid, Aphis gossypii, are common greenhouse pests. Only one microbial insecticide, the Beauveria bassiana-based BotaniGard (strain GHA), is available for use against aphids in U.S. greenhouses. We conducted laboratory assays to identify additional strains of effective fungi. Adult aphids were exposed to 13 isolates of four Hyphomycetes (B. bassiana, Verticillium lecanii, Metarhizium anisopliae and Paecilomyces fumosoroseus). While both aphid species were highly susceptible to most isolates (LC50 <100 spores/mm2 for 10 isolates), in all cases high rates of aphid reproduction were observed prior to death. To evaluate effects of fungal infection on fecundity, adults were treated with high rates (>1000 spores/mm2) of four isolates, and offspring produced prior to death were counted. Compared to controls, reproduction by M. persicae was not affected by any of the fungi, whereas that of A. gossypii was significantly reduced by exposure to all fungi tested except commercial strain GHA. However, adult A. gossypii still increased their numbers 15-20 fold prior to succumbing to infection, suggesting that to identify isolates capable of controlling aphid populations, pathogen screening should be directed against nymphal stages. In screens using a single dose (ca. 1000 spores/mm2) of the 13 strains tested against adults, 1st instar nymphs proved less susceptible than adults, with M. persicae the more susceptible of the two species. However, one B. bassiana isolate (ARSEF 5494) was highly virulent, causing greater than/equal to 80% mortality for nymphs of both species. The commercial strain, GHA, was effective against the green peach aphid but was among the least effective of the isolates tested against the melon aphid. More extensive screening of 40 isolates against nymphs of both species is currently underway.