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Wine industry fights off moths while on alert for sharpshooters

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For vintners, grapegrowers and hospitality professionals across the valley, rows of tightly manicured grapevines translate to a multimillion-dollar wine industry and, ultimately, their livelihoods.

For invasive pests, the same vines amount to nothing more than an quick snack.

This harsh truth has caused local agricultural officials to mount an all-out offensive against such pests - one fought in the field, as well as in the hearts and minds of valley residents.

Greg Clark, Napa's assistant agricultural commissioner, notes recent efforts against the European grapevine moth have made strides toward uprooting the bug permanently.

The moth - whose October 2009 discovery in Napa County marked the first time the species had been found in the United States - feeds on both flower clusters and berries of the grape vine, meaning a severe infestation has great potential to ruin a vintage.

To combat the moth, the county' Agricultural Department has implemented pheromone traps - a measure Clark says helps detect the moth within valley vineyards - as well as insecticide treatments and mating disruption techniques administered with the help of the California Department of Food and Agriculture.

The measures, officials say, appear to be working.

At this point last year, the Agricultural Department had located roughly 80,000 moths caught in detection traps, Clark said. This year, according to counts given earlier this month, only 57 moths had been detected by the traps.

"It's really been a huge success, well beyond anything we might have imagined," Clark said.

As the battle against the European grapevine moth continues, county officials are mounting another campaign against a pest that has yet to gain a foothold in the valley - the glassy-winged sharpshooter.

Should the sharpshooter take hold, the results could be catastrophic, officials said.

"European grapevine moths can damage a vintage," Clark said. "Glassy-winged sharpshooters can destroy an industry."

The sharpshooter, a large "leafhopper"-type insect, is native to northeastern Mexico and uses piercing mouth parts to feed on liquid within various plant species.

For grapegrowing communities, the concern over the sharpshooter is the sharpshooter's ability to spread Pierce's disease, a fatal illness for grapevines that contributes to millions of dollars in grower losses each year in Napa County.

While the disease already exists locally, Clark said it is contained to mainly riparian growth areas and spread by the native - and much less dangerous - blue-green sharpshooter.

Blue-greens travel only a few yards into a vineyard and feed from the softer, leafier portions of the plant. If the infection is contained to the vine's leaves, workers can trim off the affected area before it spreads.

The larger glassy-winged sharpshooter is a much stronger flier, making it capable of carrying the infection deep into a vineyard. The pest also feeds from the woody section of the plant, potentially affecting the entire vine.

"We always say that the glassy-winged sharpshooter is kind of like taking a lit match to gasoline," Clark said. "It's particularly well-suited to spread this bacteria."

Between 1998 and 2000, Southern California's Temecula wine region provided a full-scale demonstration of just how devastating the pest could be.

After a glassy-winged sharpshooter infestation - and subsequent Pierce's disease outbreak - roughly 840 acres of Temecula Valley vineyards, nearly 40 percent of the region's total acreage, had to be destroyed.

The outbreak dealt a devastating blow to the Southern California wine industry - at least $20 million, some officials say.

To prevent such a disaster from happening locally, agricultural officials have implemented an aggressive inspection program. All nursery shipments from outside Napa and Sonoma counties are to be checked for sharpshooters or their egg sacs.

In addition, the county's Agricultural Department designates each May as "Glassy-Winged Sharpshooter Awareness Month," hoping to spread awareness of the dangers posed by the pest, while encouraging residents to purchase their plants from local vendors.

Some of the county's more visible efforts feature "Sharpie," a human-sized sharpshooter replica, and ad campaigns show a mock Facebook page asking people not to "friend the bug."

"We really want to remind people, and put it in front of people on an annual basis, that the glassy-winged sharpshooter continues to pose a threat to our agricultural economy," Clark said. "While their might be some humor in the delivery, there really is a serious message behind it."

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