Submitted to: American Society for Microbiology
Publication Type: Abstract Only
Publication Acceptance Date: June 3, 1999
Publication Date: N/A
Technical Abstract: The commercial use of microbial pathogens of insects as biopesticides requires the development of low-cost methods of producing and stabilizing these agents. Spores of the fungus Paecilomyces fumosoroseus have been shown to rapidly infect and kill the silverleaf whitefly (Bemisia argentifolii), a serious agronomic pest which has become resistant to numerous chemical controls. A submerged culture method was developed for rapidly producing high concentrations of desiccation tolerant spores of P. fumosoroseus. Using our production medium and protocol, 1-2 x 10**9 spores/ml were produced after 2 days growth. When these spores were produced in media containing an appropriate source and concentration of nitrogen, 70-80% of the spores survived freeze-drying or air-drying. The survival of air-dried spores of P. fumosoroseus stored at 4 deg C was enhanced when air-drying was performed at relative humidities greater than 65%. Spores of P. fumosoroseus obtained using our production method, whether fresh or dried, have been shown to be more effective in killing the silverleaf whitefly than aerial-produced conidia of P. fumosoroseus. These studies suggest that liquid culture produced spores of P. fumosoroseus represent a commercially promising biopesticide for the control of the silverleaf whitefly.