Submitted to: Society for Invertebrate Pathology Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 9/6/1996
Publication Date: N/A
Technical Abstract: One of the major hindrances preventing the widespread use of fungal entomopathogens in pest management programs is the difficulties encountered in developing reliable formulations with long shelf-life and high activity. At the Bioactive Agents Research Unit of the National Center for Agricultural Utilization Research (USDA, ARS), we have been examining different surplus agricultural commodities as formulation ingredients for the fungal entomopathogen Paecilomyces fumosoroseus(PFR). PFR blastospores in liquid production medium were mixed with different ratios of ingredients such as corn starch, modified corn flour, trehalose, sucrose, dextran, gums (carrageenan and xanthan), and oil, among others. The formulations were then freeze dried and kept at 4 deg C. Formulations were assessed for blastospore survival based on a comparison of blastospore numbers prior to freeze drying with percentage recovery at different periods of time after freeze drying. Determinations of colony-forming units were made using the standard plate count method. Results indicate that the blastospores are tolerant to desiccation as indicated by survival following lyophilization. For most formulations, blastospore survival decreased sharply with increased storage time. One notable exception are the formulations containing Buffalo corn starch, modified corn flour, sucrose and oil.