Authors
Philippe E. Rolshausen, Department of Botany and Plant Sciences, University of California, Riverside 92521;
Kendra Baumgartner, United States Department of Agriculture–Agricultural Research Service (USDA-ARS), Davis, CA 95616;
Renaud Travadon, Department of Plant Pathology, University of California, Davis 95616;
Phillip Fujiyoshi, USDA-ARS, Davis;
Jérome Pouzoulet, Department of Botany and Plant Sciences, University of California, Riverside; and
Wayne F. Wilcox, Department of Plant Pathology and Plant Microbe Biology, Cornell University, Geneva, NY 14456
Abstract
Eutypa dieback of grapevine is caused by Eutypa lata in production areas with Mediterranean climates in California, Australasia, Europe, and South Africa. Eutypa dieback has also been described in the colder, eastern North American vineyards where cultivars adapted from native Vitis spp. (e.g., Vitis × labruscana ‘Concord’) are primarily grown. However, the causal agents associated with the diseases in this region have not been conclusively identified. Examination of 48 vineyards showing symptoms of dieback in the northeastern United States (Connecticut, Massachusetts, Michigan, New York, Ohio, and Rhode Island) and Ontario, Canada revealed that vineyards were mainly infected by Eutypa spp. other than E. lata. Multigene phylogenies (internal transcribed spacer ribosomal DNA, β-tubulin, and RNA polymerase II) of isolates recovered from these vineyards indicated that Eutypa dieback is caused primarily by an undescribed Eutypa sp. and E. laevata. Eutypa sp. was recovered from 56% of the vineyards examined, whereas E. laevata and E. lata were less far common (17 and 6%, respectively). Fruiting body morphology and spore dimensions supported phylogenetic separation of the three taxa. Pathogenicity tests conducted on Vitis vinifera ‘Chardonnay’ in the greenhouse and in the field verified that all three species were able to cause wood canker and to infect pruning wounds, respectively.
