In a bid to stave off regulatory intervention, the Californian wine sector is to introduce an environmental code of conduct next week. The Wine Institute and the California Association of Winegrape Growers said they will publish a code of "sustainable" environmental practices for the region's wine companies who account for more than 90% of US total wine production.

Environmentalists have charged the industry with contributing to soil erosion, watershed loss and pollution, but have also said the voluntary code, which has taken two years to complete, may not go far enough.

The code, a 360-page document, addresses water, land and pesticide use. It urges self-regulation by California grape growers and wine makers. "To maintain our standing as a world-class competitor in the global marketplace, we believe it is better to avoid unnecessary legislation by self-governance," the California Wine Institute said.