ARS | Publication request: Evaluation of Beauveria bassiana (Balsamo) Vuillemin (Deuteromycota: Hyphomycetes) strains isolated from varroa mites in southern France

Submitted to: Journal of Apicultural Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: May 12, 2006
Publication Date: August 16, 2006
Citation: Meikle, W.G., Mercadier, G., Girod, V., Derouane, F., Jones, W.A. 2006. Evaluation of Beauveria bassiana (Balsamo) Vuillemin (Deuteromycota: Hyphomycetes) strains isolated from varroa mites in southern France. Journal of Apicultural Research.

Interpretive Summary: Fungi that cause diseases in varroa mites might be useful in controlling the mites in beehives. Eight strains of these fungi were found growing on varroa mites collected from beehives in southern France. Two of these fungal strains were tested in the laboratory by treating varroa mites and then placing the varroa mites to feed on bee pupae. Several strains of disease-causing fungi from the collection at the European Biological Control Laboratory were tested as well. Of the two strains of fungi collected from the mites, both killed most of the mites in less than 8 days. Of the five other strains tested, four killed most of the mites in 5 days or less. Strains of fungi found in beehives would be good candidates for a project to develop a biopesticide against varroa mites.

Technical Abstract: Entomopathogenic fungi are currently being considered as alternatives to chemical pesticides for controlling varroa mites of honey bees. Varroa mites were collected from 112 beehives in southern France and evaluated for the presence of entomopathogenic fungi. Eight strains of Beauveria bassiana were isolated. Two of these strains were subsequently used in bioassays of varroa mites, along with five strains of Metarhizium anisopliae collected either from termites or from soil samples. Six of the 7 isolates evaluated significantly reduced mite survivorship compared to mites in the control group.