Apidologie 39 (2008) 247-259
DOI: 10.1051/apido:2007057

Impact of a treatment of Beauveria bassiana (Deuteromycota: Hyphomycetes) on honeybee (Apis mellifera) colony health and on Varroa destructor mites (Acari: Varroidae)

William G. Meikle¹, Guy Mercadier¹, Niels Holst², Christian Nansen³ and Vincent Girod<sup>4

1</sup>  European Biological Control Laboratory, USDA - ARS, Campus International de Baillarguet, CS 90013 Montferrier sur Lez, 34988 St. Gely du Fesc, France
²  University of Aarhus, Faculty of Agricultural Sciences, Department of Integrated Pest Management, Flakkebjerg, 4200 Slagelse, Denmark
³  Texas A&M University, Texas Agricultural Experiment Station, 1102 E FM 1294, Lubbock, Texas 79403, USA
⁴  ADAPRO LR-CRALR, Maison des Agriculteurs, Mas de Saporta CS 30012, 34875 Lattes, France

(Received 21 May 2007 - Revised 20 October 2007 - Accepted 27 October 2007 - Published online 12 February 2008)

Abstract - In 2 experiments bee colonies in southern France were treated with conidia of a Beauveria bassiana isolate collected from Varroa mites in the region. Objectives were to evaluate treatment effect on colony weight, adult bee mass, and capped brood and honey, and on Varroa fall onto sticky boards. Treatments included conidia formulated with either wax powder or wheat flour, flour alone, or control. Treatment did not affect colony health. Colonies treated with conidia and wax powder had higher mite fall compared to controls while those treated with conidia and wheat flour did not. The proportion fallen, infected mites in both conidia treatments was higher than controls for up to a week. Higher mite fall and infection rates were observed in treated hives in the 2nd, smaller experiment. The relationships between dosage and proportion fallen, infected mites, and between ambient temperature and infection duration, were examined. Future experiments will explore Varroa control using conidia.

Key words: Apis mellifera / Varroa destructor / Beauveria bassiana / biopesticide / formulation


© INRA, DIB-AGIB, EDP Sciences 2008