Glickman Announces New Research to Combat Pierce's Disease

WASHINGTON, April 14, 2000--Agriculture Secretary Dan Glickman today announced a new $500,000 research partnership to protect vulnerable vineyards from the microbe that causes Pierce's disease. USDA's Agricultural Research Service and Brazilian scientists will work together to sequence the genome of the microbe that causes Pierce's disease.

"By working together to identify the microbe's genetic makeup, we may be able to design new and powerful strategies to thwart it," said Glickman, who met last month in Temecula with California's growers concerned about the impact of Pierce's disease in their vineyards.

In Northern California, Pierce's disease has chronically attacked vineyards, costing growers $33 million from 1995 to 1997 alone. In California's Temecula Valley, south of Los Angeles, the disease has caused an estimated $6 million in damage to vineyards since 1997.

Pierce's disease is caused by a bacterium, Xylella fastidiosa. It can be carried by a half-inch-long insect known as the glassy-winged sharpshooter, which arrived in Southern California in the mid-1990s. The pest can harbor Xylella in its gut, then move it into plants when it punctures grapevine stems to feed on nutritious sap. Once inside a grapevine, X. fastidiosa bacteria multiply, blocking the flow of water and nutrients. Severely infected vines die. Pierce's disease affects wine, table, and raisin grapes. Neither the insect carrier nor the disease harms humans.

The ARS and Brazilian scientists in this joint research effort intend to discover the sequence of all of the genes in the Xylella strain that is infecting Temecula Valley grapevines.

Other Xylella research at ARS:

• Preparing U.S. for the CVC (citrus) pathogen
  (12/28/98)
• Xylella leaf scorch attacks U.S. trees
  (2/17/98)

Edwin L. Civerolo, with ARS in Davis, Calif., will lead the project jointly with Andrew J.G. Simpson of the Ludwig Institute for Cancer Research at São Paulo. Simpson is DNA Coordinator of the Organization for Nucleotide Sequencing and Analysis at São Paulo, where scientists sequenced the genome of a related Xylella strain that causes disease in citrus, making them the first in the world to sequence the genome of a plant pathogen.

The American Vineyard Foundation and the California Department of Food and Agriculture will each contribute $62,500 to the research, matching USDA funding of $125,000. The São Paulo State Research Foundation in Brazil will contribute $250,000 to the effort, which is expected to take less than a year to complete.

Scientific contact: Judy St. John, ARS National Program Staff, Beltsville, Md., phone (301) 504-6252, fax (301) 504-4663, jsj@ars.usda.gov.