Dissertation
CHARACTERIZING MECHANISMS OF ACARICIDE RESISTANCE IN THE TWOSPOTTED SPIDER MITE, TETRANYCHUS URTICAE
Doctor of Philosophy (PhD), Washington State University
01/2019
Handle:
https://hdl.handle.net/2376/108443
Abstract
The twospotted spidermite Tetranychus urticae Koch is a generalist herbivore pest that feeds on over 1100 host plant species. These host plant include many highly valued crops like hops, ornamental, and numerous other crops of economic importance. Acaricides are the cornerstone of mite management programs in most cropping systems. Unfortunately, T. urticae has an unrivaled ability to develop resistance to diverse chemistries of acaricides. This necessitates the need to identify the mechanisms of resistance to acaricides by T. urticae. Knowledge of the mechanisms enabling resistance and quantifying its prevalence in specific T. urticae populations are essential to developing effective integrated T. urticae management strategies.
Chapter one of this thesis documents the status of information with respect to the underlying mechanisms of T. urticae’s adaption to the mostly used acaricides and reviews different approaches for effectively monitoring resistance in T. urticae populations.
In chapter two, the focus is on the mechanisms of resistance to mite growth inhibitors in T. urticae populations endemic to hops in the pacific northwestern USA. Bioassay methods were compared for evaluating the ovicidal activity of etoxazole, clofentezine and hexythiazox. It was determined that the mechanisms of resistance to these MGIs in PNW hop infesting T. urticae populations was facilitated by a I1017F mutation in the chitin synthase 1 gene concurrent with enhanced metabolic detoxification by cytochrome P450(s) and carboxylesterase.
Chapter 3 is an evaluation on the phenotypic resistant status of 35 T. urticae populations sampled from commercial hop yards in the PNW in the summer of 2016 to the synthetic acaricides fenpyroximate, spirodiclofen and etoxazole. The mechanisms of resistance to major acaricide groups were also determined.
In chapter 4, T. urticae populations from peppermint and adjacent silage corn fields in central Washington were evaluated for their phenotypic and genotypic resistance to multiple acaricides.
Lastly in Chapter 5, the effect of physiological resistance in T. urticae strains on their behavioral response to acaricides was examined. The irritancy and repellency of acaricide susceptible and resistant strains of T. urticae depend on the doses of the acaricide tested and their levels of tolerance to the acaricides.
Metrics
17 File views/ downloads
21 Record Views
Details
- Title
- CHARACTERIZING MECHANISMS OF ACARICIDE RESISTANCE IN THE TWOSPOTTED SPIDER MITE, TETRANYCHUS URTICAE
- Creators
- Adekunle W Adesanya
- Contributors
- DOUGLAS B WALSH (Advisor)FANG ZHU (Committee Member)LAURA C LAVINE (Committee Member)Elizabeth BEERS (Committee Member)
- Awarding Institution
- Washington State University
- Academic Unit
- Entomology, Department of
- Theses and Dissertations
- Doctor of Philosophy (PhD), Washington State University
- Number of pages
- 170
- Identifiers
- 99900581709201842
- Language
- English
- Resource Type
- Dissertation