Insecticide resistance management in the ectoparasitic mite, varroa destructor of honey bee, apis mellifera populations and susceptibility of this invasive alien pest to fungal pathogens

The honey bee Apis mellifera is critical for honey production and crop pollination. The ecto-parasitic mite Varroa destructor is currently the most serious threat to beekeeping. More than 40% of honey bee colonies have died within the last four years due mainly to Varroa mite and diseases. Populations of Varroa mite have developed resistance to miticides used for control, and there is an urgent need for alternative control strategies. This study was carried out to monitor for resistance to conventional and new generations of insecticides and to assess the pathogenicity of Varroa mite to fungal isolates. Cadavers of Varroa mite were collected from an Apiary located in Quincy, FL and brought to the laboratory in Tallahassee, FL for bioassays. The infected cadavers were surface-sterilized and plated on Petri dishes containing Sabouraud maltose agar and they were examined daily for the presence of external fungal hyphae. Data indicated that populations of Varroa mite were resistant to Fluvalinate, Coumaphos, Malathion and Cypermethrin but susceptible to neonicotinoid (imidacloprid, acetamiprid), pyrazole (fenpyroximate) and pyrole (chlorfenapyr) groups of insecticides.  DNA fingerprinting of unknown fungal revealed the presence of saprobes and two pathogenic fungal isolates related to Metarhizium anisopliae and Beauveria bassiana.