Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/19/2004
Publication Date: 10/5/2004
Citation: Elzen, P.J., Westervelt, D., Lucas, R. 2004. Formic acid treatment for control of Varroa destructor (Mesostigmata: Varroidae) and safety to Apis mellifera (Hymenoptera: Apidae) under southern U.S. conditions. Journal of Economic Entomology. 97(5):1509-1512. Interpretive Summary: The varroa mite, Varroa destructor, is the most serious pest affecting honey bees in the U.S. Several compounds have been registered for its control, but varroa has developed resistance to these compounds across the U.S. We tested a delivery system of formic acid for its efficacy in controlling varroa, as well as its toxicity to adult and larval honey bees. While not highly effective, the results indicate that with improved delivery methods formic acid may be an alternative compound for use in the U.S. We also observed early toxicity of formic acid to developing brood, but this effect lessened with time.
Technical Abstract: The efficacy of a formic acid formulation was field tested for control of honey bee parasitic mite Varroa destructor Anderson and Trueman under environmental conditions of the southern United States. This formulation gave 39.8% control at the end of a six week treatment period, significantly different from an untreated control, but equivalent control to that achieved by an industry standard of coumaphos. Under relatively warm winter conditions in deep South Texas, formic acid did not cause significant adult honey bee mortality compared to coumaphos, but did cause initial mortality of developing eggs and brood. This effect on brood was lessened as the treatment period progressed. As resistance by V. destructor to the two acaricides registered for its control in the U.S. continues, formic acid could provide an alternative compound to use as part of an Integrated Pest Management approach.