Compatibility of a microsclerotial granular formulation of the entomopathogenic fungus Metarhizium brunneum with fungicides

Abstract

The compatibility of microsclerotial granules of the entomopathogenic fungus Metarhizium brunneum (Petch) strain F52 with fungicides (chlorothalonil, iprodione, propiconazole, pyraclostrobin+metconazole, and propiconazole+trifloxystrobin) was determined. In vitro, chlorothalonil was not detrimental to conidial production and viability at all concentrations (1–1000 mg a.i. (active ingredient) l−1). Iprodione reduced conidial production at ≥ 100 mg a.i. l−1 but had no effect on viability. Propiconazole reduced conidial production at ≥ 10 mg a.i. l−1 and reduced viability at 1000 mg a.i. l−1. A pyraclostrobin+metconazole combination reduced conidial production at ≥ 10 mg a.i. l−1 and viability at ≥ 100 mg a.i. l−1. A propiconazole+trifloxystrobin combination reduced conidial production at all concentrations and viability at ≥ 100 mg a.i. l−1. In the greenhouse, propiconazole suppressed colony forming unit (CFU) counts at both low and high rates. Chlorothalonil and iprodione had no inhibitory effect on fungal growth. The number of CFUs recovered did not differ significantly ten, 20 or 30 days after treatment. This study provides baseline information for the potential commercial use of the microsclerotia in pest control.