This leafhopper lives up to its name and moves from one plant to another. Vines, which produce grapes for wine and table consumption, are delicious targets for the xylem-sucking insect. The GWSS drills into the main rootstock of the vine and penetrates the nutrient canals of the xylem. While sucking out the plant’s fluid, insect deposits bacteria into the vine, causing Pierce’s disease.
Built like a stealth bomber, this sleek insect is about half an inch long with a mottled dark-brown body and yellow speckling about the head. It is twice as large as other common species of sharpshooters. The underside of its abdomen becomes charcoal in color as the insect ages.
Most leafhoppers are weak flyers, but the GWSS can travel miles during its life span. Other sharpshooters simply do not fly as far as the glassy-winged and seem to be more susceptible to temperature variation. The GWSS also appears in greater numbers since it has an extensive host plant range of 73 species of plants in 35 different families.
The glassy-winged sharpshooter has a voracious appetite. It can consume 100 times its body weight in plant material per day during its three- to nine-month life span. The GWSS produces two generations a year in southern California where the counties of Kern, San Bernardino, Santa Barbara, Venture, Los Angeles, Riverside, Orange, and San Diego have reached infestation levels.
In the case of the grapevine, the GWSS feeds on the plant by inserting its needle-like mouthparts into the plant’s xylem, sucking out the nutrients. If that were all it did, it would simply be a nuisance. Bacteria logged in its gullet are deposited into the central core artery system of the attacked vine. The plant’s response to this invasion is to choke off the arteries, which move the nutrients around the plant. The result is lethal: the plant’s main rootstalk dies in one to three years.
If California’s grape growing areas reach levels of infestation throughout the state in the future, the GWSS will have played a pivotal role in spreading Pierce’s disease throughout the vineyards of California, devastating the state’s $33 billion-a-year wine industry.