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ARS Home » Pacific West Area » Davis, California » Crops Pathology and Genetics Research » Research » Publications at this Location » Publication #271849
Title: New Phomopsis species identified from wood cankers in eastern North American vineyards.

Author
item Fujiyoshi, Phillip
item ROLSHAUSEN, PHILIPPE - University Of California
item Castlebury, Lisa
item MIZUHO, NITA - Virginia Polytechnic Institution & State University
item Baumgartner, Kendra

Submitted to: Phytopathology
Publication Type: Abstract Only
Publication Acceptance Date: 3/1/2011
Publication Date: 6/1/2011
Citation: Fujiyoshi, P.T., Rolshausen, P., Castlebury, L.A., Mizuho, N., Baumgartner, K. 2011. New Phomopsis species identified from wood cankers in eastern North American vineyards.. Phytopathology. 101:S56.

Interpretive Summary: Phomopsis cane and leaf spot, caused by the Ascomycete fungus Phomopsis viticola, is a destructive fruit and foliar disease in eastern North American vineyards. The pathogen typically attacks green tissues, but can also cause wood cankers, presumably due to infection of pruning wounds, as is the case for most canker pathogens of grape (e.g., Eutypa lata). If pruning wounds are an infection court for P. viticola, then controls for preventing infection of green tissues may not prevent pruning-wound infection. Accordingly, we surveyed the Phomopsis community (teleomorph Diaporthe) from wood cankers in vineyards of the northeastern US (CT, MA, MD, MI, NH, NJ, NY, OH, RI, VA, VT) and southeastern Canada (Ontario, Quebec), and evaluated the susceptibility of pruning wounds to infection by the Phomopsis species recovered. We used conidial dimensions, colony growth on potato dextrose agar, and phylogenetic analyses of nuclear loci (rDNA internal transcribed spacer region, elongation factor subunit 1-alpha, actin), to identify P. viticola from wood cankers and two new species not previously reported from grape: Diaporthe eres and a species with DNA sequences identical to isolates identified as P. fukushii in Japan. Pathogenicity tests on Vitis labruscana ‘Concord’ and V. vinifera ‘Chardonnay’ in Geneva, NY demonstrated that pruning wounds of both are susceptible to infection by strains of all three Diaporthe/Phomopsis species.

Technical Abstract: Phomopsis cane and leaf spot, caused by the Ascomycete fungus Phomopsis viticola, is a destructive fruit and foliar disease in eastern North American vineyards. The pathogen typically attacks green tissues, but can also cause wood cankers, presumably due to infection of pruning wounds, as is the case for most canker pathogens of grape (e.g., Eutypa lata). If pruning wounds are an infection court for P. viticola, then controls for preventing infection of green tissues may not prevent pruning-wound infection. Accordingly, we surveyed the Phomopsis community (teleomorph Diaporthe) from wood cankers in vineyards of the northeastern US (CT, MA, MD, MI, NH, NJ, NY, OH, RI, VA, VT) and southeastern Canada (Ontario, Quebec), and evaluated the susceptibility of pruning wounds to infection by the Phomopsis species recovered. We used conidial dimensions, colony growth on potato dextrose agar, and phylogenetic analyses of nuclear loci (rDNA internal transcribed spacer region, elongation factor subunit 1-alpha, actin), to identify P. viticola from wood cankers and two new species not previously reported from grape: Diaporthe eres and a species with DNA sequences identical to isolates identified as P. fukushii in Japan. Pathogenicity tests on Vitis labruscana ‘Concord’ and V. vinifera ‘Chardonnay’ in Geneva, NY demonstrated that pruning wounds of both are susceptible to infection by strains of all three Diaporthe/Phomopsis species.