METHODS FOR MASS-PRODUCTION OF MICROBIAL CONTROL AGENTS OF GRASSHOPPERS AND LOCUSTS

Abstract

The success of microbial control programmes often depends on an adequate mass-production method for the agent used. The pathogens with potential for use against grasshoppers and locusts vary widely in the ease with which they can be mass-produced. Obligate pathogens such as grasshopper entomopoxviruses, mermithid nematodes and Nosema locustae Canning are currently restricted to culture in living systems. Liquid fermentation is usually employed for the production of non-obligate pathogens such as bacteria, some fungi and nematodes, but in some cases the propagules produced in liquid culture are not amenable to formulation and application. Conidia of hyphomycete fungi can be produced on the surface of liquid media, on solid substrates or in diphasic systems. Production on solid substrates has been adopted for production of steinernematid and heterorhabditid nematodes and some fungi. Diphasic liquid-solid fermentation combines the benefits of both systems and is used mostly for mass-production of hyphomycete fungi such as Metarhizium flavoviride Gams & Rozsypal and Beauveria bassiana (Balsamo) Vuillemin. Increased commercial interest in biological control is likely to accelerate the development of improved and more economical methods for the mass-production of microbial control agents.