|AGUILAR, CHRISTIAN - Washington State University|
Submitted to: Phytopathology
Publication Type: Abstract Only
Publication Acceptance Date: 5/15/2015
Publication Date: 11/1/2015
Citation: Aguilar, C., Xiao, C., Mazzola, M. 2015. Management of bull’s-eye rot of apple using pre- and postharvest fungicides. Phytopathology. 105:S4.4.
Technical Abstract: Bull’s-eye rot caused by Cryptosporiopsis kienholzii, Neofabraea alba, N. malicorticis and N. perennans is a common postharvest disease of apple and pear in the US Pacific Northwest. Fruit infection by these causal fungi occurs in the orchard and is latent at harvest. A primary practice for control of this disease is the pre-harvest application of chemical sprays in the orchard, and drenching of fruit with postharvest fungicides prior to cold storage. In this study, the efficacy of pre- or post-harvest fungicide applications for disease control on fruit inoculated at two different time-points with either C. kienholzii or N. perennans was monitored. Fruit were treated with either one of three pre-harvest fungicides, (Zinc dimethyldithiocarbamate, pyraclostrobin + boscalid, and thiophanate-methyl) or one of three postharvest fungicide drenches, (fludioxonil, pyrimethanil, and thiabendazole) to determine an effective chemical control strategy for management of this disease. In general, thiophanate-methyl, pyrimethanil or thiabendazole significantly (P < 0.05) reduced incidence of fruit decay caused by either C. kienholzii or N. perennans relative to the no treatment control. Although both thiophanate-methyl and thiabendazole provided effective disease control, integration of both chemistries into a disease management program is discouraged as both fungicides share the same mode of action.