Napa Ag Commissioner Retires

Dave Whitmer successfully fought grapevine pests during 33-year career

by Paul Franson
European grapevine mother Napa
Retired Napa County ag commissioner Dave Whitmer consults a map of locations the European grapevine moth had been detected prior to a 2010 meeting about the pest.

Napa, Calif.—One of the California wine industry’s longest serving and most effective agricultural officials just ended his service to the farmers of Napa County, and now he’s turning to helping its disadvantaged people.

Napa County agricultural commissioner Dave Whitmer officially retired Dec. 20 after 33 years with the department, 20 as agricultural commissioner.

During his tenure, he saw an ongoing succession of pathogens including insects, nematodes, viruses, fungi and other challenges to America’s most prestigious grapegrowing area.

From Phyllorexa to the European grapevine moth, he was involved in programs that battled vineyard pests, and he thinks the latest pestilence, the red blotch virus, will be conquered, too.

Glassy-winged sharpshooter
Of all those threats, Whitmer is perhaps most proud of stopping the glassy-winged sharpshooter. In 1999-2000, Temecula, Calif., was attacked by the GWSS, a vigorous insect that carries Pierce’s Disease and can fly long distances.

Pierce’s Disease was a serious threat to wine grapes, though it first infected citrus in Temecula. Eventually it spread to vineyards, causing widespread devastation as vines withered and died.

“We already had problems with the native blue green sharpshooter here,” Whitmer said, “and it can’t fly very far from its typical habitat along rivers and creeks. I dreaded the thought of what a stronger version could do.”

Using a quarantine and inspection, and working with growers, commercial nurseries and agricultural advisors, Napa and other counties restricted the bug’s movement. “We’ve kept it out of Napa Valley for 13 years. I consider that pretty amazing.”

Still, Whitmer’s work in controlling the bug remains unfinished. Glassy-winged sharpshooters have not established themselves in Napa County, but every plant shipment into the county could harbor them. Inspections and quarantine of plants continue.

European grapevine moth
Local growers are grateful to Whitmer for his work in largely eradicating populations of another pest, the European grapevine moth.

“We observed the first European grapevine moths in 2009, but we didn’t know what we had because our traps didn’t draw the insects. Their last flight for the year was over.”

They soon identified the invader, but not before counting 100,000 EVGMs in traps in 2010. This bug is relatively unusual because it contaminated grapes rather than weakening or killing vines. Infected grapes couldn’t be used for winemaking.

To fight the pest, Whitmer said he needed experts who had studied the insect to both publicize the need to eliminate the bug and coordinate programs to do so. He turned to Gennaro Giliberti, director of agriculture for the province of Florence in Italy. Andrea Lucchi, a professor at the University of Pisa, gave local grapegrowers advice about the best methods for fighting the moth.

The county and state set up traps, treated vines, removed fruit and flowers from abandoned or ornamental vineyards and kept the county under quarantine. Traps, vine treatments and pheromone releases that interrupt the moths’ mating patterns have helped destroy most of the populations.

This aggressive action including isolation and pesticides—both conventional and organic versions—virtually wiped out the moths. Only 40 were found in 2013.

As those with Integrated Pest Management experience know, however, you have to maintain vigilance and continue monitoring and perhaps treatment. “If we keep on, we have a chance to eradicate the EGVM,” he said hopefully.

The task will be up to Whitmer’s successor, however. That’s Assistant Agricultural Commissioner Greg Clark, who has worked closely with Whitmer.

Following Teddy Roosevelt’s lead
Though he carried a big stick as agricultural commissioner with police powers, Whitmer rarely exercised them. Instead, he spoke softly, and people listened.

Whitmer worked closely with industry, individual growers and vineyard managers, nurseries and experts from the University of California, Davis. “It’s a unique public-private partnership,” he declared. “The growers have been tremendous. They’ve done what we asked when we asked them to.”

He is also famous for using common sense, a quality he admits isn’t always found among government agencies.

Whitmer was born in Napa Valley and earned a degree in biology from California State University, Chico, then returned to Napa and became an agricultural biologist in the Ag Commissioner’s Office. He became deputy agricultural commissioner in 1986, then commissioner.

In addition to protecting the county’s valuable grapevines, Whitmer has also been a leader in encouraging other agriculture including small farms and food gardens at restaurants and elsewhere, removing many bureaucratic impediments to their success.

In recognition of his service, the Napa Valley Grapegrowers awarded Whitmer the first “Ed Weber Award,” named after the Napa County farm advisor who died in 2007.

What’s ahead
Whitmer said he plans to travel with his wife, Loie, who also just retired, in the immediate future. His is shifting his talent from grapevines to people, helping organize an anti-poverty program called Circles, which he hopes to bring to Napa County to help break the cycle of poverty and reduce the economic divide between low-income families and the wealthy.

As a popular figure in Napa County’s largest industry, Whitmer has been approached by people who would like him to bring his ability to get things done to public office. He only says that he has no plans at present.

And as for his successor, the biggest new challenge is red blotch virus. “Growers have been dealing with it for a long time. They just didn’t know what it was,” Whitmer said. Though new tools for detection and methods of cleaning vines will help, the industry may once again have to turn to isolation.


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