The greatest threat ever to the existence of the California wine industry has forced US vice president Al Gore to declare a federal emergency.The US government has pledged a staggering $22 million as part of a $36.6m joint State-federal effort to combat a disease that could wipe out the California wine industry, according to leading industry figures.The cause of all this panic is Pierce's Disease and in particular the vine feeding bug that spreads this bacterial infection, the Glassy-winged Sharpshooter.The bug, officially known as Homolodisca coagulata, is according to California's Governor Gray Davis "the single largest threat to our grape, raisin and wine industries in a very long time."The bug is blackish-brown and about a centimetre long. With a relentless appetite it feeds on the grapevine, but also transmits Pierce's disease, which kills the vine by choking it of its water supply.Pierce's disease has existed in isolated parts of the State for a number of years. However, the arrival of the Sharpshooter from the south-eastern United States, on ornamental flower shipments, has put in place a devastating chain of vine destruction.Last year the bug attacked Temecula Valley, northeast of San Diego, destroying as much as 50% of the region's 1,200 hectares and causing $30m of damage.Worryingly for the premium producers of the Napa and Sonoma Valleys the bug has now been spotted as far north as Alameda County, while eggs have been found on plants within California's two most famous regions.Chris Brook-CarterFor a full report see just-drinks this Friday