Throughout the last five decades, European Honey bee (Apis mellifera) colonies have been heavily damaged by invading Varroa mites (Varroa destructor), and, more recently, small hive beetles (Aethina tumida). These pests infest A. mellifera colonies throughout Virginia, with V. destructor feeding upon the lipids of their hosts and spreading viruses, and A. tumida feeding extensively on hive products and brood. Because V. destructor has historically demonstrated acaricide resistance, this study examined V. destructor resistance to three common acaricides (amitraz, coumaphos, and tau-fluvalinate) throughout the three geographic regions of Virginia using glass vial contact bioassays; the results showed no resistance in the sites tested. To gain better insights into A. tumida pharmacology, several known acetylcholinesterase (AChE) inhibitors and three novel insecticides (previously shown to have low mammalian toxicity) were tested against an A. tumida laboratory colony through in vivo and in vitro bioassays. The results of these bioassays indicated that coumaphos was most selective and topically effective against A. tumida, while only one experimental compound was selective against A. tumida, with 29-fold less potency than coumaphos. These results can help apiculturists in making informed pest management choices and can lead to future studies further examining V. destructor resistance and optimizing A. tumida insecticide treatments. / Master of Science in Life Sciences / Beekeepers throughout the world have experienced great economic loss and observed a troubling decline in European Honey bee colonies over the past fifty years due to Varroa mite infestations. Varroa mites feed on the fat body of bees, depriving them of nutrients and infecting them with various diseases. Attempts made to control Varroa mites with synthetic chemicals throughout the years have led to acaricide resistance. To look at resistance in Virginia’s mite populations, resistance testing was performed on Varroa mite populations throughout the three geographic regions of Virginia, and these studies showed that there was not resistance in these populations. Another significant hive pest that is increasingly prevalent in the United States is the small hive beetle (SHB), which feeds on bee brood and hive products. SHB management tactics are still being explored, and this project tested various known insecticide treatments against small hive beetles and bees, as well as three insecticide treatments that were designed for mosquito control and have low toxicity to mammals. The results of this study showed that, of the insecticides tested, coumaphos was the most selective against SHB. This information can help beekeepers in Virginia make informed choices when deciding how to treat Varroa mite infestations, and can add to the knowledge base of those fighting small hive beetle infestations.
| Identifer | oai:union.ndltd.org:VTETD/oai:vtechworks.lib.vt.edu:10919/100994 |
| Date | 11 June 2019 |
| Creators | Roth, Morgan Alicia |
| Contributors | Entomology, Gross, Aaron D., Tignor, Keith R., Wilson, James M. |
| Publisher | Virginia Tech |
| Source Sets | Virginia Tech Theses and Dissertation |
| Detected Language | English |
| Type | Thesis |
| Format | ETD, application/pdf, application/pdf, application/pdf |
| Rights | In Copyright, http://rightsstatements.org/vocab/InC/1.0/ |
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