RT Journal Article SR Electronic T1 Preventing Trunk Diseases with Fungicide Applications to Pruning Wounds in Washington Wine Grapes JF American Journal of Enology and Viticulture JO Am J Enol Vitic. FD American Society for Enology and Viticulture SP ajev.2022.22019 DO 10.5344/ajev.2022.22019 A1 Kendra Baumgartner A1 Renaud Travadon A1 Phillip T. Fujiyoshi A1 Maria Mireles A1 Michelle Moyer YR 2022 UL http://www.ajevonline.org/content/early/2022/12/08/ajev.2022.22019.abstract AB Background and Goals Grapevine trunk diseases in the Columbia River Basin of eastern Washington include Cytospora dieback, Eutypa dieback, and Esca. Although some of the causal fungi are known (as Cytospora viticola, Eutypa lata, and Phaeomoniella chlamydospora, respectively), basic epidemiology is not. This makes it difficult to time management practices. The common assumption is that these pathogens infect through pruning wounds during the dormant season, as has been shown for causal fungi of some grapevine trunk diseases in California. As such, we evaluated fungicides for protecting wounds after pruning under eastern Washington conditions.Methods and Key Findings In March of 2019, 2020, and 2021, we evaluated the protection efficacy of pyraclostrobin + fluxapyroxad and thiophanate-methyl sprayed within 3 days of pruning, at an established Vitis vinifera ‘Chardonnay’ vineyard in Prosser, WA. Within 2 days of fungicide treatment, C. viticola, E. lata, or P. chlamydospora (2,000 spores per wound) were inoculated separately onto spurs, and molecular-detection attempts were made 5 to 8 weeks later (after budbreak). Compared to water-treated spurs, detection rates of C. viticola and P. chlamydospora from thiophanate-methyl-treated spurs were lower in all three study years. Detection rates of E. lata from thiophanate-methyl-treated spurs were lower in one year.Conclusions and Significance This suggests that dormant-season spray applications of thiophanate-methyl as a pruning-wound protectant can reduce grapevine spur infection by these pathogens. Little-to-no rain during the dormant season in eastern Washington may limit opportunities for disease spread, but winter injury to the permanent, woody structure of the vine may create additional infection courts.