Definition: Pierce's disease (P.D.)

Since 1995, a new, more virulent attack has been threatening the vineyards of Southern California and is rapidly spreading northwards. This time, the insect, a leafhopper (glassy-winged sharpshooter - GWSS), which is a vector for the bacterium, is spreading very quickly throughout all areas of these crops in California. The bacterium is capable of destroying a vine in two years (desiccation). There is currently no solution, but the government and the states concerned have just released funds to conduct accelerated research to combat both GWSS and the disease itself.

The temperate regions of Europe are also at risk because the insect is present there. In regions with harsh winters, the bacterium cannot survive the cold. There are no resistant grape varieties. Chardonnay and Pinot Noir are particularly susceptible. At the end of the first half of 2000, no fewer than eleven counties were affected, including Sacramento in the north, relatively close to the famous Napa Valley. No matter how much money is now being poured into research to combat this scourge, the results will take time. Not enough research has been done over the past 120 years. We will have to pay the price for this.