THE ROLE OF FUNGI IN THE CONTROL OF GRASSHOPPERS

Fungi are among the most important microbial pathogens of grasshoppers with potential for development as biological control agents. Unlike m ost other insect pathogens that must be ingested to initiate disease, fungi generally invade insects via the external cuticle. The most comm on fungi that are pathogenic to grasshoppers are Beauveria bassiana, M etarhizium anisopliae, Metarhizium flavoviride, Sorosporella sp., and fungi in the Entomophaga grylli complex. A review of the latest inform ation on the development of these fungi as microbial control agents of grasshoppers is presented. Species in the E, grylli complex are being used in classical biocontrol. This has resulted in controversy as the re are indigenous nonpest grasshopper species that may be affected thr ough introduction of the nonindigenous fungal strains. Beauveria bassi ana and M, flavoviride are being developed for inundative control. The se fungi can be mass produced and applied with equipment used for conv entional pesticides. Conidia are applied either at ultralow volume in oil, as oil emulsions, or as bran-bait formulations. Field trials in A frica and North America have demonstrated significant grasshopper redu ctions. Improvements in formulation and inoculum targeting may further improve their efficacy.