During drought years, we often experience large VMB populations, putting Napa vineyards at increased risk for crop damage and pest spread. Respond accordingly by scheduling early interventions to reduce populations.

Follow the newsletter link for an early April update on VMB populations.

Three leafhopper species--western grape, variegated and Virginia creeper--are present in Napa vineyards. Both variegated and Virginia creeper are invasive species, whose range has expanded considerably in Napa in the last 10 years. Proper identification of vineyard leafhoppers is critical to development of a successful management strategy. Access the newsletter link below for a "Quick Reference Guide to North Coast Vineyard Leafhoppers".

Follow the link to the newsletter below for more information on the status of resistance testing for grape powdery mildew for the DMI (FRAC 3) fungicides. 

Vine mealybug has been found on recent nursery shipments of green-growing vines in the North Coast region. 

Follow the newsletter link below to learn more. The newsletter can be used as training tool for crews inspecting vines as they are received. 

In Napa County, staff of the Agricultural Commissioner inspect all incoming shipments of green-growing vines and nursery plants. If you are expecting a shipment, contact the Agricultural Commissioner's office: (707) 253-4357

In early September 2015, the California Department of Food & Agriculture confirmed the presence of thousand cankers disease of walnut in Napa County. 

Access the newsletter below for additional information on this fungal disease and the beetle that moves it from tree to tree. 

On June 24, 2015, staff of the Napa County Agricultural Commissioner found one male Western Grapeleaf Skeletonizer in a pheromone-baited trap in a vineyard on Tubbs Lane in Calistoga. 

UCCE Advisors Lucia Varela and Monica Cooper developed a "Monitoring Guide for Western Grapeleaf Skeletonizer" so that vineyard owners, growers and workers could familiarize themselves with the pest's life stages and feeding habits.

Please use the newsletter link below to access the Monitoring Guide (English and Spanish versions). 

If you find this pest or feeding damage in Napa County please contact the office of the Agricultural Commissioner: 707-253-4357, agcommissioner@countyofnapa.org OR contact UC Cooperative Extension: 707-253-4221, cenapa@ucanr.edu

For additional information on biology and management of this pest, access the UC IPM Pest Management Guide for Western Grapeleaf Skeletonizer. 

In April, we observed leaf symptoms in select vineyards consistent with feeding damage by arboreal camel crickets. 

For photos and additional information, access the newsletter using the link provided below. 

Dr. Arturo Calderon, Postdoctoral scholar, USDA and UC Davis has released an instructional video (in Spanish) on the use of the pressure bomb to measure grapevine leaf water potential. 

We hope you will find this video to be a useful training tool.  

http://www.youtube.com/watch?v=83FXDi8Vkxg

We have updated our newsletter addressing phylloxera on resistant rootstocks.

Follow the newsletter link below to read our updated report.

In January, Dr. Gubler and I visited a vineyard that seemed to have very clear symptoms of a trunk disease (Eutypa or Botryosphaeria). Yet when we looked closer, we determined the symptoms were not caused by a pathogen...link to the newsletter below to see photographs and read our full report.