Grapevine viruses pose a severe threat to the sustainability of California viticulture.  Growers are losing contract dollars as wineries reject grape loads due to virus-induced ripening problems.  The good news is that there are virus management strategies which growers can implement right now in the short-term, which can be taught through real-world, hands-on integrated outreach from a team of growers, extension personnel, PCAs, and scientists.  With the right communication, a long-term cooperative virus strategy can save the California industry from devastating future losses.

The Lodi Winegrape Commission has been actively studying the California grapevine virus situation since 2017.  The Commission’s Research, Education, & Communications Committee has formed two teams which have been instrumental in gathering information, creating educational materials, and offering real-world, practical outreach for our winegrowing community: the Lodi Mealybug Biocontrol Research Focus Group and the Lodi Grapevine Virus Research Focus Group.

The second grant-funded LEAFROLL VIRUS TAILGATE TALK took place on October 17th, 2019.  We started off by sharing updated leafroll virus management strategies we’ve learned from researchers around the world and local experiences.  Aaron Lange (LangeTwins) and Charlie Starr IV (Viticulture Services) discussed how they train a virus scouting crew, how they map and rogue infected vines, and the associated costs.  Then, we went into the vines with the Lodi Grapevine Virus Research Focus Group and other volunteer experts to check out virus symptoms on previously-tested vines, discuss vine mealybug biocontrol options, learn how to properly take virus testing samples, review maps showing rogueing of leafroll-infected vines over time, learn about ant control, and discuss the mystery (sudden) vine collapse.  Attendees took home a new “Grapevine Virus Testing 101” informational booklet, filled with tips on how to get started with virus testing.  To get a copy of this booklet or other virus-related educational information, contact Dr. Stephanie Bolton at

In-the-vine learning stations, set up for the October 2019 LEAFROLL VIRUS TAILGATE TALK hosted by the Lodi Winegrape Commission with funding support from the American Vineyard Foundation and the CDFA PD/GWSS Board. Photo by Dr. Akif Eskalen.

Funding support from the American Vineyard Foundation and the CDFA PD/GWSS Board has allowed us to develop practical virus outreach for our winegrowing community.  A big thanks to in-the-vine station leaders Dr. Kris Tollerup & Mark Shimozaki (ant bait research update), Matt Frank & Melinda Costigan (virus testing), Charlie Starr IV & Tia Russell (virus scouting), Larry Whitted & Chris Storm (mealybug biocontrol), Loraine Lee & Sara Goldman (vine mealybug pheromone mating disruption and trapping), Aaron Lange (virus mapping and rogueing), and Dr. Akif Eskalen, Dr. Neil McRoberts, & Paul Precissi (mystery/sudden vine collapse).

If you missed the LEAFROLL VIRUS TAILGATE TALK, you can still check out the resources below (also available on our new virus resources page,

Ted Rieger reviewed the event in his article, “A Virus Scouting and Vine Rogueing Program in Lodi Vineyards” published on November 1, 2019, for Wine Business.

If you’re reading this, you may also be interested in a MYSTERY/SUDDEN VINE COLLAPSE UPDATE.  Approximately 140 people gathered in Lodi on October 1st to hear an update from Dr. Maher Al Rwahnih, Dr. Akif Eskalen, and the Lodi Winegrape Commission regarding the mystery or sudden vine collapse.  Luckily, Ted Rieger captured the meeting well in his Wine Business article, “Sudden Vine Collapse May Be Associated with Combination of Virus Pathogens,” published on October 7th, 2019.

SAVE the DATE for the third and final MEALYBUG & VIRUS OUTREACH MEETING on April 9, 2020, at the Cabral Ag Center in Stockton.  All are welcome!

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