Thesis
Management of apple anthracnose canker (Neofabraea malicorticis) in western Washington
Washington State University
Master of Science (MS), Washington State University
2017
Handle:
https://hdl.handle.net/2376/102035
Abstract
In western Washington, cider apples (Malus ×domestica Borkh.) are an emerging crop in the region but a major obstacle to planting new orchards is the widespread occurrence of apple anthracnose canker, caused by the fungal pathogen Neofabraea malicorticis (H.S. Jacks). The pathogen induces tree cankers that can kill newly planted trees, structurally weaken established trees, and is the primary factor limiting long-term orchard productivity in the region. Three research studies were conducted to investigate methods for management of apple anthracnose canker in western Washington. The first study tested if Bordeaux mix (BM) could prevent infection by N. malicorticis when trees were inoculated with or without wounding in Nov. 2015. By 11 weeks after inoculation, a canker developed in all treatments except the BM + no wound + inoculation treatment. However, due to the low rate of successful inoculations, there was no significant difference among treatments in the number and size of cankers that developed. The second study evaluated 5 fungicides for their ability to inhibit canker expansion and prevent the development of new infections. In 2016, the fungicides were applied every 3 weeks from Mar. to Oct. as curative treatments, as the trees were naturally infested with cankers. In 2017, the fungicides were applied every 3 weeks from Feb. to Apr. as preventative treatments, as the trees were not visibly infected prior to the study. While canker expansion was observed throughout the 2016 study (P < 0.0001), the fungicides significantly reduced canker expansion compared to non-treated cankers (P < 0.003). In 2017, new infections developed throughout the study period regardless of fungicide treatment (P = 0.39). The third study evaluated the efficacy of cauterization (CAU) and chemical treatments with and without canker excision (CE) to manage established cankers in two experiments. While canker size at time of treatment differed across experiments (P < 0.0001), the relative response to each treatment was similar. The application of chemical treatments with CE inhibited canker expansion, whereas CE alone or CAU did not. In both experiments, none of the treatments resulted in successful eradication of the pathogen or prevented the development of new infections.
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Details
- Title
- Management of apple anthracnose canker (Neofabraea malicorticis) in western Washington
- Creators
- Whitney Garton
- Contributors
- Carol A. Miles (Chair)Mark Mazzola (Committee Member)Lisa Wasko DeVetter (Committee Member) - Washington State University, Horticulture, Department of
- Awarding Institution
- Washington State University
- Academic Unit
- Horticulture, Department of
- Theses and Dissertations
- Master of Science (MS), Washington State University
- Publisher
- Washington State University; [Pullman, Washington] :
- Identifiers
- 99900525141101842
- Language
- English
- Resource Type
- Thesis