Tolerance of an entomophagous fungus (Lecanicillium muscarium, Beijing-P strain) against pesticides

Abstract

The tolerance of the entomophagous fungus Lecanicillium muscarium to eight pesticides using a poisoned medium method in the laboratory was evaluated. The purpose was to identify compatible combinations between biopesticides based on pathogenic fungi and conventional pesticides. Pyridalyl slightly inhibited the germination of L. muscarium spores and very slightly inhibited hyphal growth at low concentrations. The maximum inhibition rate of pyridalyl was <30%. Difenoconazole very slightly inhibited the germination of L. muscarium of conidia, and thiamethoxam and dimethomorph both very slightly inhibited hyphal growth. In most treatments, the maximum inhibition rates of difenoconazole, dimethomorph, or thiamethoxam were <20%. Phoxim at a low concentration slightly inhibited both L. muscarium conidial germination and hyphal growth (maximum inhibition rate, <25%). The minimum inhibition rate of most chlorothalonil, triadimefon, or tetraconazole treatments exceeded 60%. At low concentrations, pyridalyl and phoxim showed weak inhibitory effects, and therefore, may be compatible with L. muscarium. These data will support recommendations for the use of pesticides in integrated pest management programmes that involve L. muscarium as the biocontrol agent.