The Glassy-Winged
Sharpshooter (GWSS)

The glassy-winged sharpshooter was first reported in California in 1994, but probably arrived in the state in the late 1980s. It is native to the southeastern United States and northeastern Mexico. It feeds on the xylem fluid of many plants. This sharpshooter builds up large populations on a diverse array of host plants and is a strong flyer, traveling greater distances than native sharpshooters.


The combination of Pierce’s disease (PD) and a highly mobile vector creates a dynamic and dangerous situation for California. California’s first indication of the severe threat to the wine industry posed by this new disease and vector combination occurred in Riverside County in 1999, when over 300 acres of grapevines infested with GWSS were destroyed by PD. Losses continued to mount in Temecula and other infested areas in following years, eventually exceeding 1,100 acres statewide by 2002. Today, GWSS infestations are present in 12 counties.

Statewide Impact

Xylella fastidiosa, the bacterium that causes PD, also causes serious diseases in other plants. These include commercial crops such as almonds, citrus, peaches, plums, alfalfa, and many ornamental plants produced by the state’s commercial nursery industry. Agricultural crops are the most visible and quantifiable targets, but decorative plants, landscaping, highway medians, and other non-agricultural plantings are also at risk.

Glassy-winged sharpshooters

Contain the Spread

The glassy-winged sharpshooter has established itself in much of Southern and Central California, so total eradication of the insect from the state is not feasible. The Pierce’s Disease Control Program continuously monitors the state to confirm that non-infested areas remain free of infestations and to quickly find any new infestations. The program works to contain the spread of GWSS through its nursery, area-wide management, and biological control programs. Read more about the PDCP's GWSS suppression and containment activities.

Once it was determined that GWSS had established itself in California, the United States Department of Agriculture and California Department of Food and Agriculture established area-wide control programs in several Southern California regions. Those programs have become an important part of the overall effort to limit the spread of GWSS and PD. Area-wide management programs are conducted in Fresno, Kern, Madera, Riverside, and Tulare counties.

California Department of Food and Agricu