Preventing Trunk Diseases in the Vineyard: Choosing the Best Practices

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

Submitted to: Trade Journal Publication
Publication Type: Trade Journal
Publication Acceptance Date: 11/22/2015
Publication Date: 1/3/2016
Citation: Baumgartner, K., Travadon, R., Kaplan, J. 2016. Preventing Trunk Diseases in the Vineyard: Choosing the Best Practices. Wine and Viticulture Journal 31(January/ February):51-54.

Interpretive Summary: Over years of research on control of grapevine trunk diseases, field testing has identified three practices (delayed pruning, double pruning, and applications of pruning-wound protectants), which prevent and limit infections of grapevine pruning wounds by the spores of the fungal pathogens. No one study has compared the efficacy of three practices to all of the fungal pathogens. Nonetheless, because the published studies used controlled inoculations, followed by attempts to recover the pathogens from the inoculated pruning wounds, we can use these data to make general comparisons of disease-control efficacies across studies. Here we highlight disease-control efficacies estimated from several key publications on prevention of trunk diseases. Given the variation in disease-control efficacies between years within studies, among studies, and among specific pathogens, there is great uncertainty about the timing of preventative practices. Until detailed knowledge is available on the impacts of environmental conditions on infection, as well as the ‘healing’ process of grapevine wounds, we are left to make uniform assumptions about efficacy. Nonetheless, the more wounds protected each year, the better. Adopting practices that prevent disease establishment in early years, soon after vineyard establishment, and implementing these practices annually over a vineyard lifespan, give growers the best chance of offsetting the negative effects of trunk diseases over a 25-year vineyard lifespan. In the future, greater effort is likely needed to inform growers of the benefits of early adoption when they decide how to manage their vineyards.

Technical Abstract: Over years of research on control of grapevine trunk diseases, field trials identified cultural and chemical practices that prevent and limit infections of pruning wounds by the spores. These practices include delayed pruning, double pruning, and applications of pruning-wound protectants (e.g., thiophanate-methyl, boric acid). No one study has compared the efficacy of all such preventative practices to all trunk pathogens. Nonetheless, because the published studies used controlled inoculations, followed by attempts to recover the pathogens from the inoculated pruning wounds, we can use these data to make general comparisons of disease-control efficacies across studies. Here we highlight disease-control efficacies estimated from several key publications on prevention of trunk diseases. Given the variation in disease-control efficacies between years within studies, among studies, and among specific pathogens, there is great uncertainty about the timing of preventative practices. Until detailed knowledge is available on the impacts of environmental conditions on infection, as well as the ‘healing’ process of grapevine wounds, we are left to make uniform assumptions about efficacy. Nonetheless, the more wounds protected each year, the better. Adopting practices that prevent disease establishment in early years, soon after vineyard establishment, and implementing these practices annually over a vineyard lifespan, give growers the best chance of offsetting the negative effects of trunk diseases over a 25-year vineyard lifespan. In the future, greater effort is likely needed to inform growers of the benefits of early adoption when they decide how to manage their vineyards.