Eutypa dieback in northern California vineyards

Authors: Baumgartner, Kendra; TRAVADON, RENAUD - University Of California

Submitted to: Trade Journal Publication
Publication Type: Trade Journal
Publication Acceptance Date: 11/1/2013
Publication Date: 11/1/2013
Publication URL: http://www.lodigrowers.com/eutypa-dieback-in-northern-california-vineyards-part-ii-of-ii/
Citation: Baumgartner, K., Travadon, R. 2013. Eutypa dieback in northern California vineyards. Lodi Grapewine Commission. Trade Journal Publication. Available: www.lodigrowers.com/eutypa-dieback-in-northern-california-vineyards-part-ii-of-ii/

Interpretive Summary: In 1959, Eutypa dieback was recognized as a serious problem in apricot orchards in Santa Clara County, California. Symptomatic trees showed extensive ‘gumming’ near rotted sections of the bark around branch scars. A more severe symptom was the sudden death of branches and sometimes of entire trees. In the laboratory, isolations of the fungus Eutypa lata suggested that the same disease described as Eutypa dieback of apricot in South Australia was present in northern California. Early disease surveys identified spores of this fungus in apricot orchards in the eastern Bay Area. Because similar spore-searching efforts in vineyards of the Northern San Joaquin failed to find spores, spores infecting newly-established grapevines were assumed to originate from the east Bay. Our recent work on genetic similarities among isolates from these different regions suggests that the majority of spores infecting Northern San Joaquin Valley vineyards come from local vineyards and apricot orchards. Inoculations under controlled conditions in the greenhouse showed that the fungus shows no preference for either host, suggesting that spores from grape are similarly aggressive (or not) on apricot and vice versa.

Technical Abstract: In 1959, Eutypa dieback was recognized as a serious problem in apricot orchards in Santa Clara County, California. Symptomatic trees showed extensive ‘gumming’ near rotted sections of the bark around branch scars. A more severe symptom was the sudden death of branches and sometimes of entire trees. In the laboratory, isolations of the fungus Eutypa lata suggested that the same disease described as Eutypa dieback of apricot in South Australia was present in northern California. Early disease surveys identified spores of this fungus in apricot orchards in the eastern Bay Area. Because similar spore-searching efforts in vineyards of the Northern San Joaquin failed to find spores, spores infecting newly-established grapevines were assumed to originate from the east Bay. Our recent work on genetic similarities among isolates from these different regions suggests that the majority of spores infecting Northern San Joaquin Valley vineyards come from local vineyards and apricot orchards. Inoculations under controlled conditions in the greenhouse showed that the fungus shows no preference for either host, suggesting that spores from grape are similarly aggressive (or not) on apricot and vice versa.