Evaluation of the resistance of the mite Varroa destructor to the fluvalinate in colonies of honey bees (Apis mellifera) in Yucatan, Mexico

The constant application of pyrethroids for controlling the mite Varroa destructor has caused the appearance of populations of resistant mites to this product in several parts of the world. With the purpose of detecting the possible existence of populations of resistant mites to the fluvalinate in the State of Yucatan, one of the main honey producer states in Mexico, 12 samples were gathered from each apiary, selecting four apiaries where fluvalinate was used in constant way for the control of V. destructor during five years, and a similar quantity of samples coming from apiaries where methods of alternative control have been used during a. similar time. To determine from the mites the percentage of mortality to the fluvalinate, they were exposed to a piece of 2.5 x 1.0 cm from Apistan (R) at 10%, during 24 h. The percentage of mortality of varroas coming from apiaries treated in a constant way with fluvalinate was of 83.6 +/- 0.51 %, lower to the percentage of mortality obtained in apiaries that only received alternative treatment which was of 93.9 +/- 1.98 %, existing differences between both groups (t=-3.93, P=0.01, gl=46), This means a reduction in the percentage of mortality obtained with the fluvalinate. However, this reduction still does not reach the necessary levels that can define the presence of resistant mites, being important to change the practices that seem to reduce the levels of infestation of V. destructor. Then it is advisable the application of methods of alternative control which don't cause the resistance development in the populations of mites.