Counties Spraying Bugs to Gain Time Against Threat to Wine Industry

Crews have begun spraying San Joaquin Valley residential areas in an aggressive effort to slow the spread of the glassy-winged sharpshooter while scientists search for ways to eradicate--or live with--the voracious pest.

The infestation in the Central Valley has raised fears that a bug described as one of the most serious threats ever to California agriculture could become established in the nation’s premier farming area.

The federal government entered the fray Friday, declaring an agricultural emergency and pledging $22 million to the effort to eliminate the bug.

“This pest could devastate California’s grape and wine industry. If we don’t step up eradication and control efforts, we could see substantial agricultural losses in the future,” Vice President Al Gore said at a Menlo Park fund-raiser.

Work crews in Tulare County began spraying a pesticide called carbaryl at infested homes Tuesday. So far, 73 of 189 properties scheduled for treatment have been sprayed, said Dennis Haines, a county biologist.

Spraying is scheduled to begin this week in an area of large residential lots in Fresno.

The goal in both counties is not to eradicate the pest. “We’re trying to slow the population and buy time,” Haines said. “If we can buy a year or two, some of the research can come to fruition.”

Researchers in agricultural labs from Riverside to Davis are trying to find biological control methods, as well as working on resistant strains of grapevine.

“We’re trying to keep the population low enough so they don’t invade commercial agricultural areas” in the meantime, said Fresno County Agricultural Commissioner Jerry Prieto.

The glassy-winged sharpshooter is considered the most serious threat ever to the California grape industry, not because of its appetite, but because it can carry a bacterium, Xylella fastidiosa, that causes Pierce’s disease. The disease clogs the water-carrying tissues of the grapevine, causing it to die of thirst.

The glassy-winged sharpshooter--so named because of the needle-like proboscis it uses to puncture host plants--is native to Mexico and the southeastern United States. It invaded California a decade ago, but the danger it posed to grapevines was discovered only in the last two years, when Pierce’s disease began ravaging vines in Temecula.

So far, 20% of that region’s 2,300 acres have been lost. Worse still, agricultural officials said, 75% of the vines may be infested. The sharpshooter is believed to have been spread through nursery shipments.

By the time the threat was understood, the sharpshooter had already invaded all of Southern California. Farmers worried that it might spread north into the Central Valley, which each year harvests 230,000 acres of grapes.

The infestation of Fresno and Tulare counties confirmed their fears, but just as alarming was the threat to the world-famous Napa-Sonoma wine country and the state’s $33-billion wine industry.

Napa County Agricultural Commissioner Dave Whitmer has said that if the sharpshooter reaches the Napa Valley, it would be like “striking a match in a forest.”

With a few exceptions, residents have accepted the spraying effort. Three property owners in the Porterville community of Tulare County refused to allow their yards to be sprayed, Haines said. Several protesters showed up at a public hearing Thursday night in Fresno on plans to spray 52 homes there this week.

Commissioner Prieto said carbaryl is not a danger to residents and is commonly used by household gardeners. The U.S. Environmental Protection Agency lists it as a cholinesterase inhibitor and says prolonged exposure can cause headaches, memory loss, muscle weakness and cramps.

An environmental group questioned the wisdom of spraying residential areas.

“It’s a toxic chemical,” said Lori Schiraga, project director of the Environmental Defense Center. “Just because it’s sold over the counter by no means makes it safe.”

The research is proceeding on two fronts. Several species of tiny parasitic wasps are being studied as possible predators. But scientists must make sure they eat only sharpshooter eggs before raising them by the millions and releasing them into the environment.

Other researchers are trying to find ways to make grapevines more resistant to Pierce’s disease.

The state previously set aside $14 million to fight the pest. Friday’s emergency declaration brings the total financial commitment to $36.3 million.

At the same time, nursery operators are feeling the sting of being blamed for the bug’s spread. Gary Hayakawa, owner of Three Star Nursery in Fountain Valley, said a Fillmore nursery voluntarily stopped shipping plants north, losing $3 million, out of a sense of responsibility. Instead of making nursery operators scapegoats, “Let’s work together to see what we can do to keep from spreading” the bug further, Hayakawa said.

With $12 billion in annual sales, nursery plants are the third largest crop in California.