Moths plague California's wine country

Organic vineyards are more resilient to pests.

A fast-moving, destructive insect is spreading across Napa Valley.

The European grapevine moth has destroyed grapes in other parts of the world, so its first appearance in California wine country last fall left grape growers understandably concerned. Parts of California—which produces 240 million cases of wine per year—were put under quarantine March 4, 2010. With approximately 480,000 acres of harvestable vineyards valued at $1.85 billion under assault, some grape growers feel torn over the decision to use chemical forms of pest control.

Wineries that have a sustainable certification can be authorized to use pesticides in certain cases. For example, the Lodi Rules for Sustainable Winegrowing, which has certified 10,000 acres, winegrapes lets certifiers use a pesticide environmental impact model to determine how much and which kinds are allowable. Managers of certified organic or biodynamic vineyards, however, do not have that leeway.

Occasionally organic farmers are faced with the dilemma of sacrificing their crop for their certification, says Ann Thrupp, director of sustainability at Hopland, Calif.–based Fetzer Vineyards, the state's largest grower of organic grapes. Ultimately, these growers must weigh how important certification is “in terms of their brand identity and market placements versus possible crop loss,” says Dana Nigro, managing editor at WineSpectator.com.

However, not all hope is lost for sustainable and organic growers in California. There are natural methods that have proven effective in Europe and organic and biodynamic vineyards may be less vulnerable than those without surrounding natural habitat and biodiversity, which attract natural predators. Thrupp says Fetzer Vineyards has been “more resilient” to previous pest outbreaks in the past for that reason.

California organic growers reported more than $25 billion in gross sales in 2007, the last year for which information was available through California Department of Food and Agriculture.