The Glassy-winged Sharpshooter (GWSS) is a large leafhopper insect that can vector the deadly Pierce’s disease in grapevines. GWSS moves as egg masses on nursery stock from Southern California where the pest is widely established. The Ag Commissioner staff inspects all incoming nursery stock for signs of the pest. Napa County growers are currently battling the endemic Pierce’s disease that is spread by native insects. If GWSS were introduced into Napa County, they would be difficult and costly to eradicate and the increased losses from Pierce’s disease could devastate the local vineyard, winery, and tourism industries.