Development of novel and safer miticides is imperative to the immediate survival of honey bees and preservation of the global food supply. In Chapter One, three experiments were conducted to determine the minimal toxic concentration (MTC) of thymol-phosphate (ThP) in adult and larval honey bees and to determine the minimal effective concentration of ThP for Varroa destructor. It was found that miticidal doses of ThP killed adult and larval honey bees under long-term exposure, whereas those same doses did not kill Varroa comparable to the positive control, 50% thymol. Therefore, ThP is unlikely to be an effective miticide. In Chapter Two, we tested seven compounds in the field. Based on the laboratory bioassays conducted with thymol and thymoquinone, as well as thymol (ai) concentration of commercially available Apiguard, we determined that concentrations of 20% and 40% thymoquinone would be tested in the field. During the 2015 field trial, HopGuard ® II, and neem (low and high doses) were tested. During the 2016 field trial, brood break with oxalic acid, HiveClean®, MAQS+, Metarhizium anisopliae, 20% thymoquinone, and 40% thymoquinone were tested. Measures of mite infestations of adult bees, mite infestations in sealed brood (2015 only), residual mites, colony strength, and colony mortality were used to assess the efficacy and safety of the different treatments. Based on our findings in our experimental set-up, we would recommend HopGuard® II, HiveClean®, and MAQS+ to be used as part of a rotation of miticides. Both thymoquinone and neem oil (high dose) may be effective with further modifications.
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|Commitee:||Chiu, Joanna, Yang, Louie|
|School:||University of California, Davis|
|School Location:||United States -- California|
|Source:||MAI 57/05M(E), Masters Abstracts International|
|Subjects:||Biology, Entomology, Agriculture|
|Keywords:||Apis mellifera, Biomiticide, Hiveclean®, Hopguard® ii, Maqs+, Varroa destructor|
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