Photo by: J. K. Clark

UC Scientists collaborate to eradicate European grapevine moth from California

  • UC Scientists collaborate in multi-agency, science-based response plan to eradicate European grapevine moth from California.

UC Scientists collaborate to eradicate European grapevine moth from California

European grapevine moth (EGVM), Lobesia botrana, considered the most important insect pest of grape in Europe and the Middle East, was first detected in Napa Valley in 2009. The immature stages injure the berry, promoting development of fungal infections that result in bunch rots. While moth populations were largest in Napa County, by 2011 it had also been found in 9 other counties as far south as Fresno. In 2010, the US and California Departments of Agriculture established an eradication program to keep this insect from becoming established in grape growing regions. If established, it could cause significant economic damage resulting from export restrictions on table grapes, and it could have led to significant increases in production costs in all grape growing regions as well as greater reliance on insecticide with potentially adverse environmental effect.

Since this is an invasive pest, UC ANR academics responded rapidly—working with public and private partners and international scientists—to develop a pest management program that relied on a dual approach of deploying pheromone dispensers to disrupt mating and application of carefully-timed insecticides. UC scientists also quickly assembled information from overseas and designed research and educational programs to address California-specific questions. By late 2009, an extensive literature review describing the current knowledge of life cycle and management was published on the UC IPM Exotic and Invasive Pests webpage. Next, UC scientists mounted a multi-pronged research program to study the biology, life cycle, host range, and management practices under California conditions. This program generated information used by growers to monitor and control this pest, and information used by policymakers to address regulatory questions regarding detection and dispersal to prevent the spread of this serious pest. Our results demonstrated that low-toxicity conventional and organic insecticides gave excellent control without disrupting the natural biological controls for other grapevine pests avoiding secondary pest outbreaks. This allowed grape growers to continue to produce a competitive crop under quarantine restrictions. Information generated from field observations and research trials was reported weekly or semiweekly through UCCE Napa County EGVM newsletter. A summary of the program was published in California Agriculture October/December 2014 issue.

Over the span of seven years, the dual pest management approach was implemented and European grapevine moth detections declined from over 100,000 moths in 2010 to one moth in 2014 and none in 2015 or 2016. Subsequently, all previous 10 California infested counties have been deregulated and European grapevine moth declared eradicated from California and United States. Lifting quarantine restrictions from table grape production areas enhanced the industry’s ability to export its product and preserved community economic wellbeing. Policymakers incorporated information generated from our trials and observations into European grapevine moth regulations. This multi-agency collaboration contributed to a successful science-based response plan to a serious pest threat.