Napa County – and California – have delivered the knockout blow to the European grapevine moth after a seven-year battle.
The state Department of Food and Agriculture and United States Department of Agriculture on Thursday declared the vineyard-maiming pest eradicated. The quarantine covering the Napa Valley and other areas of the county is lifted.
“It’s a tremendous accomplishment,” Napa County Agricultural Commissioner Greg Clark said.
Echoing him, California Department of Food and Agriculture Secretary Karen Ross said in a press release it’s no easy feat to eradicate an invasive species.
No moth has been found in California since June 25, 2014. The native of southern Italy was first detected in the United States in Napa County in 2009 and later in Fresno, Mendocino, Merced, Nevada, Santa Clara, Santa Cruz, San Joaquin, Solano and Sonoma counties.
The moth larvae feed on the insides of grapes, hollowing them out and leaving excrement. That’s a nightmare image for world-famous Napa County wine country.
That first Napa Valley find took place in Oakville in the heart of the valley. Video shows swarms of the tan-brown-and-black, quarter-inch-long moths in an 11-acre block of chardonnay. By all appearances, a person casually swatting the air would hit several.
Steve Moulds of Moulds Family Vineyard – who didn’t have the moth at his Oak Knoll area property – said Thursday that the pest was “particularly noxious” for the future of viticulture.
Eradication initially looked like a hopeless dream. By 2010, the infestation reached a point that 100,000 moths were detected in Napa County in traps.
But Napa Valley Grapegrowers CEO Jennifer Putnam said then-Agricultural Commissioner David Whitmer wanted to do more than simply try to live with the moth.
“We were very aggressive about protocol and were appropriately focused on eradication rather than management,” Putnam said Thursday.
As it turned out, the moth could be wiped out given time, effort, cooperation and such tools as insecticides and mating-disrupting synthetic pheromones.
Clark said the Napa wine industry spent $49 million on the grapevine moth fight. The government spent $9.8 million in Napa, much of it federal money.
A quarantine imposed in Napa County sought to stop the spread of the moth. Grape growers could still transport grapes, but had to take such steps as under-filling or tarping bins.
“It was a nominal additional expense and certainly some extra steps were involved,” Moulds said. “But certainly all of that is now well worth it in retrospect.”
One mystery remains—how the European grapevine moth came to Napa County and California in the first place. Clark pointed out the difficulties in figuring this out. Although the Oakville discovery site was the so-called “ground zero,” the moth might have been at other locations undetected before 2009, he said.
The official end of the European grapevine moth threat had Clark smiling on Thursday. But he viewed the victory as part of an ongoing war.
“That hasn’t changed the reality that this industry and other agricultural industries face persistent pest pressures from invasive species,” Clark said.
He had an example in his office. He pulled out a yellow sticky trap paper about 10 inches by 10 inches from Kern County plastered with dozens of dead glassy winged sharpshooters.
The glassy winged sharpshooter spreads vine-killing Pierce’s disease. The Napa County website says a sharpshooters infestation would be difficult to eradicate, vine losses would be huge and jobs would be lost in the vineyard, winery and tourism industries.
Moulds said the European grapevine moth eradication is a hard-fought victory that grape growers don’t take for granted.
“Our job as well as our mission is eternal vigilance,” Moulds said.