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ARS Home » Pacific West Area » Davis, California » Crops Pathology and Genetics Research » Research » Publications at this Location » Publication #321840

Research Project: Sustainable Vineyard Production Systems

Location: Crops Pathology and Genetics Research

Title: The role of pest control advisors in preventative management of grapevine trunk diseases

Author
item Hillis, Vicken - UNIVERSITY OF CALIFORNIA
item Lubell, Mark - UNIVERSITY OF CALIFORNIA
item Kaplan, Jonathan - CALIFORNIA STATE UNIVERSITY
item Doll, David - UNIVERSITY OF CALIFORNIA - COOPERATIVE EXTENSION SERVICE
item Baumgartner, Kendra

Submitted to: Phytopathology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/6/2015
Publication Date: 4/8/2016
Citation: Hillis, V., Lubell, M., Kaplan, J., Doll, D., Baumgartner, K. 2016. The role of pest control advisors in preventative management of grapevine trunk diseases. Phytopathology. 106:339-347. doi: org/10.1094/PHYTO-10-15-0250-R.

Interpretive Summary: Diseased vineyards can have little to no profit on the capital invested. Minimizing such an economic impact depends on disease prevention, but adopting a preventative practice after infection occurs may not improve yields. Pest control advisers may play an important role in reducing grower uncertainty about the efficacy of and the need for preventative practices. Here, we surveyed pest control advisers to examine their influence over the decisions growers make about managing grapevine trunk diseases, which includes Botryosphaeria dieback, Esca, Eutypa dieback, and Phomopsis dieback. Trunk diseases significantly limit grape production worldwide and there is no cure. Our online survey revealed that advisers are aware of the challenges posed by trunk diseases, reporting that most vineyards they service have trunk diseases, and they acknowledge the fact that not managing these diseases reduces yields and the vineyard lifespan. Advisers rated both preventative and post-infection practices as effective to very effective. Despite higher cost estimates given to post-infection practices, advisers did not recommend preventative practices at higher rates. High recommendation rates were correlated with high disease prevalence for both preventative and post-infection practices; there was no preference for preventative practices in vineyards with low disease prevalence. Recommendation rates declined with increasing cost for preventative, but not for post-infection, practices. Our findings underscore the importance of clear management guidelines for advisers, emphasizing both the need for prevention and its long-term cost-efficacy.

Technical Abstract: Diseased vineyards can produce a disproportionately low ratio of yield to ecosystem dis-services, and can have little to no returns on the capital invested. Minimizing such environmental and economic impacts depends on disease prevention, but adopting a preventative practice after infection occurs may not be met with yield improvements. Pest control advisers (PCAs) may play an important role in reducing grower uncertainty about the efficacy of and need for preventative practices, which often entail future and unobservable benefits. We surveyed PCAs to examine their influence over grower decision-making, in the context of grapevine trunk diseases Botryosphaeria dieback, Esca, Eutypa dieback, and Phomopsis dieback, which significantly limit grape production worldwide and for which no curative practices are available. Our online survey revealed that PCAs are aware of the widespread nature and impacts of trunk diseases. PCAs rated both preventative and post-infection practices as effective. Despite higher cost estimates given to post-infection practices, PCAs did not recommend preventative practices at higher rates. Instead, PCAs recommended all practices more frequently in vineyards with high disease incidence; there was no preference for preventative practices in vineyards with low disease incidence. Recommendation rates declined with increasing cost for preventative, but not for post-infection, practices. Our findings highlight the challenges of crop disease prevention; even when PCAs appreciate the importance of a disease, they may not effectively recommend preventative practices before infection occurs. These challenges underscore the need for a clear outreach strategy to PCAs, emphasizing the long-term cost-efficacy of disease prevention.