Toxicological evaluation of selected acaricides on Varroa destructor and honey bees, Apis mellifera under laboratory and field conditions | ||
Menoufia Journal of Plant Protection | ||
Articles in Press, Accepted Manuscript, Available Online from 01 October 2025 | ||
Document Type: Original Article | ||
DOI: 10.21608/mjapam.2025.421160.1051 | ||
Authors | ||
. Hanan M. A Konper1; M. A Seddik,1; Sayed Mohmed Amer Ali1; Mohamed Anter2 | ||
1Department of Apiculture, Plant Protection Research Institute, Agricultural Research Center, Dokki, 12619 , Giza, Egypt. | ||
2Department of Plant Protection, Faculty of Agriculture, Al-Azhar University, Cairo | ||
Abstract | ||
The present study evaluated the acute contact toxicity and field efficacy of four acaricides; coumaphos, tau-fluvalinate, oxalic acid, and the thymol-based formulation Varoviga® against Varroa destructor and honey bee workers (Apis mellifera) at different concentrations. Laboratory bioassays demonstrated clear differences among the tested compounds. After 12 and 24 hours of exposure, coumaphos consistently exhibited the highest potency against mites, with LC50 values of 2.28 and 1.34 µg/mL, respectively, while maintaining selectivity toward honey bees (LC50= 27.33 and 18.24 µg/mL). Oxalic acid and tau-fluvalinate showed moderate toxicities to V. destructor (LC50 = 25.89–21.26 µg/mL and 32.96–24.69 µg/mL, respectively), whereas Varoviga® was the least effective (LC50 = 157.95–124.67 µg/mL). For honey bees, the toxicity ranking differed: coumaphos was most toxic (LC50 = 27.33–18.24 µg/mL), followed by oxalic acid (86.81–71.42 µg/mL), tau-fluvalinate (334.71–296.07 µg/mL), and Varoviga® (526.26–443.16 µg/mL). These patterns confirm that while synthetic acaricides provide strong control of mites, they may pose risks to bee health if overdosed. Field trials corroborated laboratory findings, with coumaphos producing the highest mite drop, closely followed by oxalic acid, while tau-fluvalinate and Varoviga® were less effective but still significantly reduced infestations compared to untreated controls. The combined results emphasize the importance of balancing acaricidal potency with honey bee safety and highlight the potential of integrating natural products such as oxalic acid and thymol formulations into rotational treatment programs to enhance sustainability and delay resistance development. | ||
Keywords | ||
Varroa destructor; honey bees; toxicity | ||
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