|AGUILAR, CHRISTIAN - Washington State University|
Submitted to: Phytopathology
Publication Type: Abstract Only
Publication Acceptance Date: 6/21/2016
Publication Date: 12/1/2016
Citation: Aguilar, C.G., Mazzola, M., Xiao, C. 2016. Bull’s-eye rot management: understanding the disease cycle of Neofabraea spp. occurring on apples grown in the Pacific Northwest. Phytopathology. 106:S4.195.
Technical Abstract: In the US Pacific Northwest, bull’s-eye rot of pome fruit, caused by Neofabraea spp., is a major quarantine concern. Of the four fungi causing this disease, Neofabraea perennans and N. kienholzii are common in north central Washington. In addition to fruit decay, N. perennans causes perennial canker and dieback of apple trees. Currently the over-seasoning strategies of N. kienholzii have not been elucidated. The objectives of this research were to determine the relative capacity of N. kienholzii to induce cankers in comparison with N. perennans, determine the timing of canker induction and fruit infection by either fungus, and to evaluate the efficacy of various fungicides for control of bull’s-eye rot. Based on the findings from this research, N. kienholzii is capable of inducing cankers however, cankers were generally smaller than those induced by N. perennans. Canker induction by both species was prevalent in October compared to other inoculation periods (p < 0.01). Fruit infection was observed at each inoculation period, however disease incidence was greatest near the end of the fruit growing season (October, P < 0.0001). Among those examined, thiophanate-methyl, thiabendazole and pyrimethanil where the only chemicals found to provide effective bull’s-eye control (P < 0.0001), yet due to modes of action and current use by industry, resistance to these fungicides is considered high risk.