EFFECTS OF REHYDRATION ON THE CONIDIAL VIABILITY OF METARHIZIUM FLAVOVIRIDE MYCOPESTICIDE FORMULATIONS

The rehydration of dried conidia of Metarhizium flavoviride was invest igated in an attempt to increase speed of kill of locusts and grasshop pers by formulations of this fungus. Conidia were dried to 4-5% moistu re content with no apparent adverse effects on viability, but rapid re hydration (by putting dried conidia directly in free water) reduced vi ability. Rehydration in an atmosphere of high humidity allowed dry con idia to absorb sufficient moisture to avoid imbibition damage. Rehydra ting and pre-germinating conidia prior to spraying (in an oil-based fo rmulation) on to the desert locust, Schistocerca gregaria, did nos dec rease the time to death, suggesting that moisture uptake by dry conidi a on the desert locust cuticle is easily achieved.