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

The success of microbial control programmes often depends on an adequa te mass-production method for the agent used. The pathogens with poten tial for use against grasshoppers and locusts Vary widely in the ease with which they can be mass-produced. Obligate pathogens such as grass hopper entomopoxviruses, mermithid nematodes and Nosema locustae Canni ng are currently restricted to culture in living systems. Liquid ferme ntation is usually employed for the production of non-obligate pathoge ns such as bacteria, some fungi and nematodes, but in some cases the p ropagules produced in liquid culture are not amenable to formulation a nd application. Conidia of hyphomycete fungi can be produced on the su rface of liquid media, on solid substrates or in diphasic systems. Pro duction on solid substrates has been adopted for production of steinem ematid and heterorhabditid nematodes and some fungi. Diphasic liquid-s olid fermentation combines the benefits of both systems and is used mo stly for mass-production of hyphomycete fungi such as Metarhizium flav oviride Gams & Rozsypal and Beauvelia bassiana (Balsamo) Vuillemin. In creased commercial interest in biological control is likely to acceler ate the development of improved and more economical methods for the ma ss-production of microbial control agents.