Napa growers detect new grape pest

Traps set to keep track of sites where bug found

By Robert Rodriguez

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A new grape pest has been discovered in Napa County, and valley grape growers are hoping it doesn't hitch a ride south.

State agricultural officials have confirmed that the European grapevine moth and larvae have been detected in the Oakville region of Napa County, one of the state's premier wine-grape growing regions.

The moth is considered a destructive pest because the larvae feed on grape bunches, ruining the berries and contributing to mold problems.

It's the first known detection of the moth in the nation.

Monica Cooper, a University of California viticulture farm adviser in Napa County, said evidence of the moths' damage began showing up several months ago, but growers did not know what it was.

"We started an investigation as more growers started reporting more of it," Cooper said.

Once the insect was positively identified, the Napa County Department of Agriculture, the U.S. Department of Agriculture and the California Department of Food and Agriculture began setting traps to determine where else the insect may be.

"This is a pest that needs to be taken seriously, and that is exactly what we are doing," said Greg Clark, assistant agricultural commissioner in Napa County.

San Joaquin Valley grape industry officials say they are keeping a close watch on what happens up north. The valley is the leading producer of raisins and a major contributor of juice concentrate.

"Anytime you have a potential pest that can feed on berries, it is a concern for all of us," said Barry Bedwell, president of the California Grape and Tree Fruit League. "And this also points out, once again, how harmful invasive species can be."

Valley grape growers have been battling the glassy-winged sharpshooter for several years. The insect is feared because of its potential to carry the vine-killing Pierce's disease.

Kent Daane, an insect-pest specialist with the UC cooperative extension, said that although no one knows how the pest arrived, he suspects international airline travel.

"People have become far more relaxed about this issue, and you see them bringing in fruit from Hawaii, China and Mexico," Daane said.

The European grapevine moth is found in Europe, the Mediterranean, southern Russia, Japan, the Middle East, and northern and western Africa.