Glassy-winged Sharpshooter (GWSS)
The Glassy-winged Sharpshooter (GWSS) (Homalodisca vitripennis) is a serious pest in California. This insect was first observed in California in 1990 and is now found throughout Southern California and portions of the San Joaquin Valley. It is a particular threat to vineyards due to its ability to spread Xylella fastidiosa, the bacterium that causes Pierce's disease. Pierce's disease kills grapevines and there are no effective treatments for it. The Glassy-winged Sharpshooter also spreads other diseases to a variety of agricultural crops and ornamental plants.
To prevent the introduction of this leafhopper into Marin County, staff inspects all incoming nursery plant shipments from infested California counties. Each year the Department inspects over a thousand shipments for GWSS. Detection traps are also placed and monitored for this serious pest.