Trunk neglect is too common

Authors: Baumgartner, Kendra; HILLIS, VICKEN - University Of California; LUBELL, MARK - University Of California

Submitted to: Trade Journal Publication
Publication Type: Trade Journal
Publication Acceptance Date: 5/22/2014
Publication Date: 5/22/2014
Publication URL: http://www.growingproduce.com/fruits-nuts/trunk-neglect-is-too-common/
Citation: Baumgartner, K., Hillis, V., Lubell, M. 2014. Trunk neglect is too common. Trade Journal Publication.

Interpretive Summary: Trunk or wood-canker diseases (including Botryosphaeria dieback, Esca, Eutypa dieback, and Phomopsis dieback) significantly limit the productive life of a vineyard. Many vineyards in California are likely infected and yield losses in severely symptomatic vineyards can reach more than 90%. Trunk diseases take a long time to develop and often become symptomatic years after infection has already occurred, at which point management options are limited. While preventative management practices are available, grape growers may be hesitant to use them due to uncertainties about cost-effectiveness and future risk of infection. We conducted a survey of attendees at the San Joaquin Valley Grape Symposium, organized and hosted by Matthew Fidelibus, University of California Cooperative Extension Specialist, held in Easton, CA, on Jan. 8. We used Turning Point, an electronic audience response system, to conduct the survey. We asked raisin growers from the southern San Joaquin Valley about two practices known to be effective in preventing trunk diseases: delayed pruning and the application of pruning-wound protectants. Survey results showed that growers use both delayed pruning and pruning-wound protectants at relatively low levels. Between 50-60% of growers never or rarely use these two practices. For both practices, about 40% of the growers reported typical first use to be in vineyards older than 13 years old. Thus, a sizable minority of growers likely start to use these preventative practices after infection has already occurred. These findings make it clear that better extension tools are needed to make a stronger case for adopting preventative practices in young vineyards.

Technical Abstract: Trunk or wood-canker diseases (including Botryosphaeria dieback, Esca, Eutypa dieback, and Phomopsis dieback) significantly limit the productive life of a vineyard. Many vineyards in California are likely infected and yield losses in severely symptomatic vineyards can reach more than 90%. Trunk diseases take a long time to develop and often become symptomatic years after infection has already occurred, at which point management options are limited. While preventative management practices are available, grape growers may be hesitant to use them due to uncertainties about cost-effectiveness and future risk of infection. We conducted a survey of attendees at the San Joaquin Valley Grape Symposium, organized and hosted by Matthew Fidelibus, University of California Cooperative Extension Specialist, held in Easton, CA, on Jan. 8. We used Turning Point, an electronic audience response system, to conduct the survey. We asked raisin growers from the southern San Joaquin Valley about two practices known to be effective in preventing trunk diseases: delayed pruning and the application of pruning-wound protectants. Survey results showed that growers use both delayed pruning and pruning-wound protectants at relatively low levels. Between 50-60% of growers never or rarely use these two practices. For both practices, about 40% of the growers reported typical first use to be in vineyards older than 13 years old. Thus, a sizable minority of growers likely start to use these preventative practices after infection has already occurred. These findings make it clear that better extension tools are needed to make a stronger case for adopting preventative practices in young vineyards.