Evaluation of some synthetic acaricides against varroa destructor (acari: varroidae) in Turkey: an ındication of resistance or misuse of fumigant amitraz?

Abstract

The parasitic mite, Varroa destructor is one of the most important agents for substantial losses in honeybee colonies throughout the world. Several acaricides consisting of synthetic and organic compounds are being used to combat mite. This study was conducted to determine the efficacies of three synthetic acaricides in naturally infested honeybee colonies at consecutive two autumn seasons. Acaricides were commercial preparations of coumaphos (liquid and plastic strips), amitraz (fumigation and plastic strip) and flumethrin (plastic and wooden strips) as a treatment group consisting of eight hives per drug. A control group was kept in both seasons. All drugs were applied as prescribed to the homogenised Varroa-infested honeybee colonies at consecutive two years. The evaluation of efficacies was based on the collected mite percentage obtained with powdered sugar method and it was calculated through Henderson-Tilton’s formula. Dropped mites onto the pollen drawers were also evaluated statistically and drugs were compared to each other. Results showed us the effective drugs (up to 90%) were amitraz plastic strip, flumethrin wooden strip and coumaphos plastic strip with 98.5%, 96.5%, and 93.2% averages, respectively according to formula if evaluated within two autumn seasons. Fumigation of amitraz is not sufficient if compared to others and the control group. This data is discussed for suspicion of the possible resistance of mites or misuse of the product with this kind of application.