Apidologie (2001) 32, 49-55

Massimo Spreafico, Francesca Romana Eördegh, Iris Bernardinelli and Mario Colombo (2001)
First detection of strains of Varroa destructor resistant to coumaphos. Results of laboratory tests and field trials
Apidologie 32 (1), 49-55
Abstract: The susceptibility of four populations of Varroa destructor to the organophosphorous acaricide coumaphos was studied. The mites were taken from apiaries kept in Lombardy (northern Italy) and tested with a laboratory assay on paraffin wax with known concentrations of coumaphos. The susceptibility of two populations to coumaphos was close to that of susceptible populations, indicated in the literature (LC₅₀ at 24 hours: 12.6 µg/g); a third population showed a significant, but slight increase in tolerance (LC₅₀ at 24 hours: 29 µg/g) while the fourth population had a much higher LC₅₀ (>200 µg/g at 24 hours). In subsequent field trials carried out in the apiary in which the latter population had been sampled, the total average efficacy of two treatments with Perizin^® (the commercial formulation of coumaphos) in colonies without capped brood was 46% (28-88% ).
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Link to article at publishers website
Database assignments for author(s): Iris Bernardinelli

Research topic(s) for pests/diseases/weeds:
pesticide resistance of pest

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Varroa destructor		Italy