Location: Bee Research Laboratory
Project Number: 8042-21000-291-075-R
Project Type: Reimbursable Cooperative Agreement
Start Date: Sep 15, 2023
End Date: Sep 14, 2027
Objective:
The ultimate goal of this project is to identify and develop potential varroacides for registration and licensing for beekeeper use. To meet this goal, the project has two research objectives (ROs). Objective 1 (RO 1) will use laboratory trials to screen dozens of candidate compounds and assess their efficacy against Varroa mites and safety for honey bees. Objective 2 (RO 2) will take compounds showing promise from laboratory trials, and run field trials using these compounds in field honey bee colonies.
Approach:
Proposed are 2 sets of activities corresponding to each of the 3 research objectives: 1- Lab screening trials of candidate compounds to determine acute toxicity of compounds to both Varroa mites (Vd) and host HBs; 2-colony-level field trials assessing effects of candidate compounds identified in RO1 on colony performance and Vd populations, and whether compound residues are found in stored honey; and 3-use of advanced methodology to elucidate the molecular mechanisms granting Vd resistance to active ingredients of current miticides. This work will begin in earnest and proceed concurrently with laboratory and field trials. Laboratory trials assessing the acute toxicity of screened compounds on Vd mites and HBs will use a widely accepted method employing 20 mL glass vials, and for HBs, 60 mL wide mouth mason jars will have their interior surfaces uniformly coated with a test compound dissolved in a suitable solvent (e.g., acetone), or the solvent alone as a negative control. A suitable positive control will be identified through screening acaricides currently used by beekeepers to both characterize the existing resistance in mite populations (RO3) and to identify an appropriate level of one acaricide demonstrating >95% mortality.
The field trials will follow established protocols for colony assessments. For each promising candidate compound identified by RO 1, there will be 4 treatment groups, each comprising 10 colonies: 1) Negative Controls, 2) Low, 3) Medium, and 4) High concentrations. Specific concentrations will be determined for each compound during RO1 dose-titration studies. Application methods will be determined for each tested compound by consensus, and may vary among test compounds, but will most likely consist of cardboard or plastic strips impregnated with compound. Frequency of compound application will also be determined by consensus and may vary among tested compounds. Every 14 days over the experimental period, (42 days), measurements of colony performance, effect of treatment on Varroa mite population, and samples of stored honey will be taken. The collection of mites to identify the reduced field efficacy of standard varroacides is described in ROs 1 and 2.
