A novel acute toxicity bioassay and field trial to evaluate compounds for small hive beetle control

Authors: KLECKNER, KAYLIN - University Of Florida; DE CAROLIS, ALESSANDRA - Instituto Zooprofilattico Sperimentale Del Mazzogiorno; JACK, CAMERON - University Of Florida; Stuhl, Charles; FORMATO, GIOVANNI - The Istituto Zooprofilattico Sperimentale Delle Venezie (IZSVE); ELLIS, JAMES - University Of Florida

Submitted to: Applied Sciences
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/23/2022
Publication Date: 10/1/2022
Citation: Kleckner, K., De Carolis, A., Jack, C., Stuhl, C.J., Formato, G., Ellis, J. 2022. A novel acute toxicity bioassay and field trial to evaluate compounds for small hive beetle control. Applied Sciences. 12:9905. https://doi.org/10.3390/app12199905.
DOI: https://doi.org/10.3390/app12199905

Interpretive Summary: The small hive beetle is a predatory pest of the western honey bee, Apis mellifera. There are only a few approved chemicals for use in the management of the beetle, and no standardized system for screening new chemicals for control. Coumaphos and permethrin are the only two insecticides currently authorized for use in small hive beetle control. Researchers at the Center for Medical, Agricultural, and Veterinary Entomology in Gainesville, FL in collaboration with scientists at the University of Florida, investigated novel methods and chemicals for assaying the potential use in population reduction for small hive beetle control. Here, we outline a detailed method for laboratory and field assays for delivering the toxic compounds of interest to the small hive beetles in treated pollen. In experiments, the chemicals acetamiprid, and fipronil were selected as potential beetle control agents. The two chemicals were compared to the effectiveness of Coumaphos. Results indicated that acetamiprid was more toxic to beetles than was coumaphos, but less toxic than fipronil. In our field trials, honey bee hives that were treated with acetamiprid and fipronil reduced the beetle populations moreso than those that did not receive a treatment. The traps containing acetamiprid treated pollen retained significantly higher numbers of dead beetles than traps containing the fipronil treatment. Overall, our method appears to provide an efficacious comparison and our results indicate that acetamiprid is a promising control agent for small hive beetle. This knowledge provides a crucial step for the development of management protocols for the small hive beetle.

Technical Abstract: Beekeepers need new registered products to control the small hive beetle (SHB), Aethina tumida, a significant pest of western honey bee (Apis mellifera) colonies. Few approved chemical controls exist, and there is no standardized system for screening compounds against SHBs. We outline a detailed method for an acute toxicity bioassay that delivers compounds via pollen. We provide a detailed method for a field trial that delivers treated pollen in traps made from modified compact disc cases. We applied both methods in proof-of-concept experiments to assess acetamiprid as a SHB control agent. Using the laboratory bioassay, we found acetamiprid ( = 20.5 µg/g) to be more toxic to SHBs than coumaphos was ( = 1250 µg/g), yet less toxic to SHBs than fipronil was ( = 1.78 µg/g). In our field trial, colonies treated with acetamiprid and fipronil significantly reduced (p < 0.001) live SHB populations over those of control colonies. Traps containing acetamiprid retained significantly higher (p < 0.001) numbers of dead SHBs than did traps containing fipronil. We outline the first detailed methods to assess the toxicity of compounds delivered in pollen for adult SHB control. Our proof-of-concept experiments showed acetamiprid to be a promising control agent for SHBs.