Oosporein was the only major secondary metabolite produced by three commercial isolates of the entomopathogenic fungus
Beauveria brongniartii in submerged cultures and on sterilised barley kernels. None of the other toxins (bassianin, beauvericin and
tenellin) normally produced by Beauveria species were detected by sensitive HPLC and MS techniques. The maximum amount of
oosporein produced in batch reactors was 270 mg l−1, after 4 days incubation, 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 detected in cockchafer larvae
infected with B. brongniartii was 0.23 mg. Melocont®-Pilzgerste, a commercial product based on B. brongniartii, was not phytotoxic
to Lepidium sativum and Phleum pratense nor were fungal metabolites detected in these indicator plants. No systemic effects of
oosporein were observed in treated pasture turf maintained for several months in the greenhouse.