Efficacy of field-isolated strains of Beauveria bassiana (Moniliales : Moniliaceae) as microbial control agents of the lesser mealworm (Coleoptera : Tenebrionidae)

Two field isolates (NC2 and NC3) of Beauveria bassiana (Balsamo) Vuillemin were evaluated as microbial control agents of the lesser mealworm, Alphitob ius diaperinus (Panzer), in a bioassay system incorporating physical charac teristics of commercial poultry houses. Both isolates produced >90% mortali ty in new litter against larval A. diaperinus at the highest application ra te (2.37 X 10(11) conidia per square meter) 2 wk after application. Neither isolate achieved as high a rate of mortality in used litter. Adult A. diap erinus were less susceptible than larvae to these isolates. At the highest application rate (2.37 X 10(11) conidia per square meter), isolate NC2 coni dia achieved 60% mortality of adults in new litter and 33% mortality in old litter. The same concentration of isolate NC3 conidia produced 68 and 33% mortality in new and used litter, respectively.