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Poster: Biology & Disease Mgmt: Chemical Control


Sensitivity of Neofabraea spp strain to newly registered fungicides.
P. SIKDAR (1), M. Mazzola (2) (1) Washington State University, U.S.A.; (2) USDA-ARS, U.S.A.

Bull’s eye rot, incited by a group of closely related fungi in the genus Neofabraea, causes significant economic loss to the Washington State apple industry. The pathogen complex is a significant limitation as it has been listed as a quarantine pathogen with a zero tolerance level for fruit shipped to China and Israel. Access to export markets for Washington State apples relies on the development of effective bull’s eye rot control methods. Previous experiments indicate that fungicide treatments containing thiabendazole and thiophenate-methyl provide effective disease control, however use of this treatment is not recommended due to the potential for development of resistance in populations of Penicillium spp., which incites the common postharvest disease, blue mold. Fludioxonil (Scholar) did not demonstrate consistently effective control of bull’s eye rot in fruit and did not limit in vitro growth of the pathogen. Additional analyses were conducted to screen Neofabraea spp. isolates for sensitivity to newer commercially available fungicides that include multiple active chemistries. Results from these trials suggest that fungicide containing fluopyram and trifloxystrobin inhibits in vitro growth of Neofabraea at a level equivalent to that of thiabendazole. In contrast, fungicide treatment containing cyprodinil with difenconazole, or solatenol alone failed to inhibit mycelial growth or spore germination in vitro.