First detection of Varroa destructor resistance to coumaphos in Argentina

MAGGI M.; RUFFINENGO S.; DAMIANI N.; SARDELLA N.; EGUARAS E.

EXPERIMENTAL AND APPLIED ACAROLOGY

SPRINGER

Año: 2009 vol. 47 p. 317 - 320

0168-8162

In Argentina, studies on Varroa destructor resistance to coumaphos are still unknown. At present, high infestation levels of V. destructor are being detected in colonies of Apis mellifera after treatment with this acaricide. The aim of the present study was to determine the LC50 of coumaphos in V. destructor from four apiaries with high mite density after treatment with coumaphos. The LC50’s were 112, 319, 127 and 133 ug/Petri dish for mites from the four apiaries. Signifficant LC50 differences were detected between resistant and susceptible mites. LC50 increased 197–559-fold when compared to the corresponding baseline, suggesting the development of resistance. These results are the first report of resistance to coumaphos in V. destructor in Argentina.