Pests & Diseases

The Napa County Agricultural Commissioner's Office is concerned about the introduction of new, exotic and destructive organisms. A significant exotic pest infestation could affect everyone in the county, through the loss of markets for farm products, increased pesticide usage and production costs. 

A comprehensive insect trapping program is facilitated by staff. Additionally, we conduct inspections of plants entering the county from throughout the state and across the country.

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Solano County Mediterranean Fruit Fly Quarantine

In late August 2017, the Solano County Agriculture Department caught a female Mediterranean Fruit Fly (Medfly) in a detection trap located in the city of Fairfield. Following the detection, a Medfly quarantine was established in the Fairfield area of Solano County by the California Department of Food and Agriculture (CDFA). Currently, 108 square miles are under quarantine in Solano County (quarantine map.)

Medfly infests over 250 wild and cultivated fruits, including citrus, stone fruits, olives, tomatoes, and peppers. Grapes are also a host of Medfly.

Napa County wineries that plan to receive wine grapes from Solano County for the 2018 harvest should contact the vineyard operators to see if their property is within the Medfly quarantine. Grape growers within the quarantine area will be conducting pre-harvest bait treatments, witnessed and certified by California Department of Food and Agriculture staff. Vineyard operators that have applied the verified treatments will be able to ship their fruit to wineries without further restrictions. If you have questions, please contact our office at (707) 253-4357.

Sentinel Trapping Program

The sentinel trapping program targets pests not known to occur in the United States, or which may occur in a very limited distribution. These specific pests have not been found in Napa County, but their introduction would pose a serious threat to the wine grape industry. Early detection of significant pests could reduce crop losses and treatment costs. It could also help prevent the spread of these pests to additional counties, states or countries, minimizing the overall impact on trade and market distribution  

The wine grape pests that are being trapped for in our sentinel program include: Grape Berry Moth, European Grape Berry Moth, Grape Tortrix Moth, Honeydew Moth, Brown Marmorated Stink Bug, and Olive Moth. We currently have approximately 1200 sentinel traps placed throughout Napa County. This program is funded by the Napa County Wine Grape Pest and Disease Control District and the County of Napa.

General Trapping Program

The goal of the general trapping program is to detect the introduction of very specific pests within Napa County through the placement of traps using pheromones, food lures or visual attractors. Our insect trapping program routinely monitors for European Grapevine Moth, Glassy-winged Sharpshooter, Vine Mealybug, exotic fruit flies, Gypsy Moth, Japanese Beetle, and Western Grapeleaf Skeletonizer (PDF)(more information). For details on these pests to go the CDFA Pests and Disease page.

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