Insect invader threatens future of California's grape-growers

In this story: A quick kill The pest has struck before RELATED STORIES, SITES

TEMECULA, California (CNN) -- By most accounts, California's wine industry expects 2000 to be a very good year. Yet a half-inch-long marauder has the state's winegrowers worried about their future.

The Homalodisca coagulata, commonly known as the glassy-winged sharpshooter, is literally sucking the life out of California's grapevines.

The insect transmits Pierce's disease while it feeds of grapevines, sucking out moisture at a rate equal to a human drinking 1,000 gallons of water a day. There is no known cure so affected vines must be destroyed.

Dozens of glassy-winged sharpshooters are showing up in state Agriculture Department traps used to track the ever-widening zone of infestation -- which now reaches toward the golden heart of California's winemaking Napa Valley.

Pierce's disease already has been identified in 11 counties, primarily in the state's southern region and San Joaquin Valley. Three dozen other counties are threatened, authorities say.

"The glassy-winged sharpshooter is the B-52 bomber of sharpshooters," says Dale Brown, a spokesman for the Napa Valley Grape Growers Association. "So if this guy gets in there, he'll go through like wildfire."

The only proven remedy is to destroy infected vines. In Temecula Vfind a cure for Pierce's disease," says Napa Agricultural Commissioner Dave Whitmer.

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Researchers continue to search for a cure before California's $2.8 billion wine and grape-growing industry is further damaged. A gene sequence has been mapped for the bacteria that causes Pierce's, for instance, and breeding continues on pest-resistant vines. Other research touches biological controls through natural predators and ways to curb bacterial growth, according to the Wine Institute.

Peterson says he's saved half of his infected vines by using plastic screws treated with antibiotics. Other growers are spraying pesticides, and California has adopted tighter restrictions on nursery plant shipments, which carry sharpshooters.

Napa grape growers say they're at especially increased risk because the region's crops are almost exclusively vineyards. There are no barriers to the sharpshooter's spread.

"The glassy-winged sharpshooter could actually take the agriculture, the grapes in this county, down," says vineyard owner Andy Beckstoffer.

So far, Piece's disease has damaged less than 1 percent of California's 554,000 wine-grape acres, the Wine Institute notes. Vineyards in the Los Angeles Basin were devastated by the pest in the 1880s, and repeat infestations caused widespread damage in the 1930s and 40s.

The glassy-winged sharpshooter was reintroduced to California in 1989 through nursery stock imported from the southern states.

CNN Financial Correspondent Casey Wian contributed to this report.

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College of Natural Resources, UC Berkeley
Overview of Pierce's Disease
Wine Institute
Napa Valley Grape Growers Association
Temecula Valley Wine Country
Folie a Deux

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