Thesis
Testing the effects of different concentrations of Metarhizium brunneum, oxalix acid and thymol on Varroa destructor
Washington State University
Master of Science (MS), Washington State University
2019
Handle:
https://hdl.handle.net/2376/103738
Abstract
Honey bees, Apis mellifera L., are beneficial insects for human nutrition and agriculture. They are important crop pollinators; contributing $15-20 billion to the agricultural economy in the United States. Many factors can lead to a decline in these utilitarian insects, and Varroa destructor, an ectoparasitic mite (Anderson & Trueman) is one of the most important worldwide. This pest, feeds on fat body tissue of honey bees, and cause collapse of untreated colonies within two years. Although beekeepers have used acaricides to control these mites, they continue to face resistance problem to the chemicals. Emerging acaricide resistance in varroa mites have compelled beekeepers to explore alternative ways to control varroa mites. The effectiveness of three non-acaricidal approaches to control varroa mites were tested under laboratory conditions. Varroa mites used for testing collected from the research beehives in Moscow, Idaho, USA. We tested application of spores of Metarhizium brunneum at concentrations of 5.7 x 10^4, 2.24 x 10^5, 5.05 x 10^5, 9.2 x 10^5, and 2.05 x 10^6 viable conidia in per ml−1, compared with oxalic acid and thymol. Materials were sprayed with a Potter Precision Spray Tower machine (Burkard Scientific, UK) and evaluated for their effectiveness on varroa mite mortality. The same number of varroa mites for each objective was used and recorded daily mite mortalities. 3.0% solution of oxalic acid and thymol killed varroa mites quickly than entomopathogenic fungi in 48h. No significant differences were observed in the virulence of mites between fungal concentrations. For the second experiment, 1.5% solution of oxalic acid and 10^4, 10^5, 10^6, 10^7 and 10^8 concentrations of Metarhizium brunneum were applied by mixing (500 µl oxalic acid and 500 µl M. brunneum). The optimal effect on varroa mite mortality was observed for the mixture solution oxalic acid with 10^8, 10^7 and 10^6 concentrations of M. brunneum. There was a noticeable difference between the mixture solutions with 10^8, 10^7 and 10^6 concentration of M. brunneum and 1.5% solution of pure oxalic acid application in 24h. The effectiveness of 105 and 104 mixture solutions were lower than other solutions.
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Details
- Title
- Testing the effects of different concentrations of Metarhizium brunneum, oxalix acid and thymol on Varroa destructor
- Creators
- Fadime Yetis
- Contributors
- Walter S. Sheppard (Degree Supervisor)
- Awarding Institution
- Washington State University
- Academic Unit
- Entomology, Department of
- Theses and Dissertations
- Master of Science (MS), Washington State University
- Publisher
- Washington State University; [Pullman, Washington] :
- Identifiers
- 99900525124801842
- Language
- English
- Resource Type
- Thesis