No European Grapevine Moths Found In Napa County Since 2013

While it’s still too soon to declare complete eradication, no European Grapevine Moths (EGVM) have been found in Napa County since 2013.

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Napa County Agricultural Commissioner Greg Clark credits a joint effort between the grape and wine industries and the federal, state, and local governments for the remarkable control of this pest over the last several years.

“This program started with the initial detection in the fall of 2009, and what was quickly identified was that we needed to bring together subject matter experts on this pest, because it was the first time it had been found in the U.S.,” Clark says.

The USDA quickly established a technical working group, which brought together experts from around the world, including Europe, where the pest is believed to originate.

Because it had already spread to 11 counties when eradication efforts began, Clark says there were questions about whether it would even be possible to eradicate it at all. “At that time, the message was, ‘if we don’t try, we’ll never know,’” he says.

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Although battling the pest required a commitment of resources and money from the industry, Clark saw it as a “pay me now or pay me later” situation. “If we don’t [work to eradicate it], people in the industry will be incurring those costs forever, because once a pest becomes established, it’s just folded into the litany of things that growers have to deal with,” he says.

The industry’s willingness to step up has played a tremendous role in the control of EGVM, and Clark adds that it helps that the pest is relatively easy to control with both organic and conventional crop protection materials, as long as they’re applied at the right time using the right rates and methods.

Mating disruption has also been instrumental in fighting EGVM. “At one point we had close to 23,000 acres in Napa County under mating disruption, and that has been an invaluable tool in complementing the insecticide treatments,” Clark says.

All told, Clark says the industry has contributed at least $50 million within Napa County to eradicate EGVM, and the government has contributed another $50 million. “That’s a lot of money, but the results speak for themselves,” he says.

The Work Isn’t Done
In order for a pest to be declared eradicated, six full generations have to pass from the last find. While there are three generations of EGVM per year from a pest management perspective (one in April/May, one in June/July and another later into the summer), the regulatory standpoint is that there are only two. (The thought is that EGVM begins overwintering as the days get shorter, so the pest may not be fully active in the third generation). That means that after the 2016 season, if no more moths are found, six generations will have passed, and eradication can be declared.

But that doesn’t mean the work is done. Napa County has developed a sentinel trapping program that monitors not just for EGVM, but other pests that could pose a serious risk. Five to seven traps have been placed per square mile to monitor for pests. “In the even that they follow the same pathway [as EGVM] or a different pathway and end up here, we’d much rather know sooner rather than later that they’re here so we can work with the industry and regulatory officials to control and eradicate them,” Clark says.

Growers must also remain vigilant. Today’s global economy creates new concerns regarding the spread of pests. There are companies that farm both in California and South America, for example, so it’s important to be sure that any plant material or equipment that comes from other areas is clean and inspected before arrival in the U.S.

“We need to make sure that people throughout the chain of decision-making understand that sanitation and cleanliness for quarantined pests is paramount and that they address that,” Clark says.

These items need to be inspected again upon arrival, too, he adds. “We’ve asked people to contact our office if they need our assistance,” he says. “We’ll send someone out to help to ensure the cleanliness of that particular item.”

With these continued efforts in place, Clark is optimistic. “We’re hopeful that about this time next year that we will have been able to declare eradication,” he says.

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