GWSS Concerns

Concerns about the Glassy-Winged Sharpshooter

The glassy winged sharpshooter is a vector (an insect or other object that can transfer a disease or other pathogen) for a devastating bacterium called Xylella fastidiosa. This bacterium causes a disease called "Pierce's" disease that can kill grape vines. Other forms of the bacterium can cause oleander leaf scorch, alfalfa dwarf, citrus variegated chlorosis and other plant diseases.

If the Sharpshooter becomes established throughout California it can spread Pierce's disease in vineyards and other diseases to agricultural crops. Potential losses could exceed $14 billion to the wine, grape, raisin, almond, alfalfa, apricot, cherry, citrus, peach and other agricultural industries in California. The Sharpshooter alone is costing The California Department of Transportation thousands of dollars because they have to replace the Oleanders that have been infected with Pierce's disease spread by the Sharpshooter. Estimates indicate it could cost $50 million to replace the Oleanders that are already planted on freeway medians in California. There is no current cure for Pierce's disease. We can not save the plants that are infected. The only way to try and save the grapevines is to cut them back to a point where the bacterium has not yet spread. However the Sharpshooter is large so it can feed near the base of the vine injecting the bacterium into the entire plant thus killing it. Even if it does not feed off of the base of the vine it is still possible to infect a major portion of the plant so that it cannot be saved. Native vectors of Pierce's disease occur in California, however native vectors of Pierce's disease do not fly as well, so will occasionally infect a few vines at the edge of a vineyard. The Sharpshooter is capable of flying about ½ mile at a time, enabling it to fly to all areas of a vineyard potentially spreading the disease to all the vines in the vineyard.

The sharpshooter can also cause problems on ornamental plants that are not effected by the disease. It is such a voracious feeder that the plants that it feeds on do not fare as well as other plants in the area. The excrement also causes a whitewashed appearance that is undesirable and can be messy. If there are enough Sharpshooters in the trees above you they can literally leave you wet from their excrement if you are under the tree. This can create a problem for people trying to play in parks or having a barbecue in an infested area.

If the Sharpshooter becomes established in California there are other economic problems that can arise. When the sharpshooter infests a region, the area is under quarantine. If this happens in a region that exports produce or even ornamental plants, the plants and fruits that need to go to market, must first be inspected. This causes delays for the grower and requires a licensed inspector to inspect the fruit or plants for the sharpshooter. Some counties, states and countries will not accept plant material from infested regions and revenue is lost. The sooner an infestation is detected the sooner it can be eradicated and declared clean and free of the Sharpshooter.