Monitoring the distribution of secondary metabolites produced by the entomogenous fungus Beauveria brongniartii with particular reference to oosporein

Oosporein was the only major secondary metabolite produced by three commerc ial isolates of the entomopathogenic fungus Beauveria brongniartii in subme rged cultures and on sterilised barley kernels. None of the other toxins (b assianin, beauvericin and tenellin) normally produced try Beauveria species were detected by sensitive HPLC and MS techniques. The maximum amount of o osporein produced in batch reactors was 270 mg 1(-1), after 4 days incubati on, while that produced on sterilised barley kernels ranged between 2.0 and 3.2 mg kg(-1), after 14 days incubation. The mean amount of oosporein dete cted in cockshafer larvae infected with B. brongniartii was 0.23 mg. Meloco nt(R)-Pilzgerste, a commercial product based on B. brongniartii, was not ph ytotoxic to Lepidium, sativum and Phleum pratese nor were fungal metabolite s detected in these indicator plants. No systemic effects of oosporein were observed in treated pasture turf maintained for several months in the gree nhouse.