Napa County Agricultural Commissioner's Office

🍇 HAVE YOU PURCHASED A GRAPEVINE RECENTLY? 🍇

The Napa County Agricultural Commissioner’s Office is asking residents to check whether they purchased a grapevine, citrus tree, or other fruit tree from Napa Costco or nearby Costco locations during April or May.

These plants may be associated with shipments containing the glassy-winged sharpshooter (GWSS), an invasive pest that threatens vineyards and backyard ornamentals.

If you have one of these plants:

• Keep it isolated in its original container.
• Do not move or transport it.
• Do not place it in the trash or compost.
• Contact our office immediately.

📞 707-253-4357
📧 [email protected]

Early detection and reporting are critical to protecting Napa County agriculture.

Thank you for helping keep our community and vineyards safe.

¿Compró usted una vid en Costco entre el 21 de abril y el 21 de mayo?
Por favor, llame a nuestra oficina para programar una inspeccion 707-253-4357.

The California Department of Food and Agriculture’s Pierce’s Disease Control Program (PDCP) is working with Costco Wholesale and county agricultural officials after invasive glassy-winged sharpshooter (GWSS) insects were found on grapevine shipments sold at select Costco locations in Northern California between April 21 and May 19. Costco is not at fault and is cooperating with our response. This is an active and evolving situation.

For the latest updates, please visit:
https://www.cdfa.ca.gov/pdcp/gwss-costco-plants.html

PUBLIC NOTICE: To support our local agricultural industry and protect our county from potential glassy-winged sharpshooter (GWSS) introduction, the Napa County Agricultural Commissioner's Office will maintain weekend hours for inspections of plants purchased at Costco in April and May.

Protecting Our Backyards from GWSS!

Did you know the glassy-winged sharpshooter (GWSS) can feed on over 300 different types of plants? While we are placing 500 traps in local vineyards this June, our residential neighborhoods are actually a major focus. This pest thrives on everyday greenery like backyard citrus, crape myrtles, and oleanders.

To protect our community, our Pest Detection team has deployed 405 yellow sticky traps across local residential areas. Our trained staff inspects these traps every two weeks, and any suspect samples go straight to the state lab for rapid identification.

Early detection is the absolute key to stopping a neighborhood infestation before it spreads. Keep an eye out for our teams in the field, and thank you for helping us keep our local yards safe!

Image description: pest detection worker placing a yellow sticky trap on a tree.

🚨 Pest Alert: Glassy-winged sharpshooter (GWSS) 🚨

We’re on high alert for this tiny insect, but why is it such a massive threat to our vineyards and gardens? It all comes down to its biology and how it behaves.

Here is what you need to know about the science behind the pest:

• GWSS is a highly mobile leafhopper that carries Xylella fastidiosa — the fatal bacterium behind Pierce’s disease. When the insect feeds, it transmits the bacteria, which blocks the plant's vascular system, cutting off water and nutrients. There is no cure, and it can kill a grapevine in just 1 to 5 years.

• Unlike native sharpshooters, GWSS can fly far and fast. This high mobility allows it to rapidly spread disease across vineyards, citrus groves, and almond orchards.

🪴 Life Stages:

Eggs:
Look for rows of eggs (up to 28) on the underside of leaves. They look like a greenish blister covered in a white, chalky secretion. Once hatched, they leave a permanent brown scar on the leaf.

Nymphs:
Wingless, olive-gray, and have prominent bulging eyes.

Adults:
Large for leafhoppers (about 1/2 inch long), dark brown-to-black with transparent wings.

Key identifier:
Look for distinctive ivory or yellowish spots on their heads.

📢 How you can help:
If you purchased grapevines or fruit trees from the Napa Costco between April 21 and May 26, 2026, please inspect your plants immediately for these biological signs and contact the Agricultural Commissioner’s office at 707-253-4357.

Early detection is our best defense!

Image description: (Top) Plant leaf with a Glassy-winged sharpshooter egg mass. (Bottom) Adult Glassy-winged sharpshooter

[👇para español👇]
⚠️ PUBLIC ALERT: Glassy-winged Sharpshooter Detected on Grapevines Sold at Napa Costco

The Napa County Agricultural Commissioner’s Office is asking residents to check any grapevine, citrus tree, or fruit tree purchased at the Napa Costco or neighboring Costco locations during April or May.

If you purchased one of these plants:
• Isolate the plant
• If possible, double-bag the plant in two secured trash bags and seal them closed
• Do NOT plant, move, return, compost, or dispose of it
• Contact the Agricultural Commissioner’s Office at 707-253-4357 or [email protected]

Early detection is critical to protecting Napa County agriculture.
Learn more and view full instructions: https://www.napacounty.gov/m/newsflash/home/detail/846
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⚠️ALERTA PÚBLICA: Se ha detectado la presencia de la chicharrita de alas cristalinas en plantas de vid vendidas en el Costco de Napa.

La Oficina del Comisionado Agrícola del Condado de Napa pide a los residentes que revisen cualquier planta de vid, cítrico o árbol frutal comprado en el Costco de Napa o en los Costcos de los alrededores durante los meses de abril o mayo.
Si ha comprado alguna de estas plantas:
• Aísle la planta
• Si es posible, métala en dos bolsas de basura bien cerradas y séllelas
• NO la plante, traslade, devuelva, utilice como abono ni la deseche
• Póngase en contacto con la Oficina del Comisionado Agrícola en el 707-253-4357 o en [email protected]
La detección temprana es fundamental para proteger la agricultura del condado de Napa.
Obtenga más información y consulte las instrucciones completas: https://www.napacounty.gov/m/newsflash/home/detail/846

[👇para español👇]
⚠️ PUBLIC ALERT: Glassy-winged Sharpshooter Detected on Grapevines Sold at Napa Costco ⚠️
The Napa County Agricultural Commissioner’s Office is asking residents to check any grapevine, citrus tree, or fruit tree purchased at the Napa Costco or neighboring Costco locations during April or May.

If you purchased one of these plants:
• Isolate the plant
• If possible, double-bag the plant in two secured trash bags and seal them closed
• Do NOT plant, move, return, compost, or dispose of it
• Contact the Agricultural Commissioner’s Office at 707-253-4357 or [email protected]

Early detection is critical to protecting Napa County agriculture.

Learn more and view full instructions: https://www.napacounty.gov/m/newsflash/home/detail/846
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⚠️ALERTA PÚBLICA: Se ha detectado la presencia de la chicharrita de alas cristalinas en plantas de vid vendidas en el Costco de Napa.⚠️

La Oficina del Comisionado Agrícola del Condado de Napa pide a los residentes que revisen cualquier planta de vid, cítrico o árbol frutal comprado en el Costco de Napa o en los Costcos de los alrededores durante los meses de abril o mayo.

Si ha comprado alguna de estas plantas:
• Aísle la planta
• Si es posible, métala en dos bolsas de basura bien cerradas y séllelas
• NO la plante, traslade, devuelva, utilice como abono ni la deseche
• Póngase en contacto con la Oficina del Comisionado Agrícola en el 707-253-4357 o en [email protected]

La detección temprana es fundamental para proteger la agricultura del condado de Napa.

Obtenga más información y consulte las instrucciones completas: https://www.napacounty.gov/m/newsflash/home/detail/846

Spring Container Recycling Event is this Thursday, May 7, 2026 8:00 am - 3:00 pm at the Napa County Calistoga yard. Please contact our office at 707-253-4357 if you have any questions.