DAVIS, Calif. -- Wine growers now have a new weapon in the war on pests that won't use harsh chemicals, researchers said.

University of California, Davis researchers released five new high-tech rootstocks in one-gallon buckets Monday for licensed nurseries.

Researchers said ideally, wine growers would graft their favorite grapevines onto these new bug-resistant root systems for a better crop.

Every year, aphids and other insects damage California's wine industry, researchers said.

"In the past we've used fumigation," lead UC Davis researcher Andy Walker said. "It's limited now and doesn't really work."

Walker and his associates said they breed these new varieties using 15 years of research on nematodes and phylloxera, or tiny worms and aphids, that attack the root systems of grape vines worldwide.

"One of the problems we have in viticulture is we don't crop rotate," Walker said. "Therefore, pests build up and become more aggressive and better adapted to feed on typical rootstocks."

Nursery owners like Dan Martinez of Martinez Orchards who have a license to grow the Walker rootstocks said it's an exciting new product they hope to offer vineyards soon.

"There is a lot of interest in what this would bring in the industry," Martinez said. "People are always looking for alternatives, especially alternatives that do not include pesticides to alleviate (pest) problems."

The nursery owner said he'll take the next year to raise the rootstocks on acres of land at his orchard in Yolo County.

"We're looking at least two years before we have any number of cuttings we can sell to customers." Martinez said. "But they'll know right away if it's working on pests."

Wine from these new grape rootstocks could be on shelves by 2013, officials said.