The glassy-winged sharpshooter is a type of leaf-hopping insect native to the Southeastern United States. On its native ground, the insect does not pose any serious problems, but as an invasive species, it puts crops in other parts of the United States at risk. Of largest concern is the grape crop in California, which is very vulnerable to infection with Pierce's disease, a bacterial infection which is carried by glassy-winged sharpshooters. As a result, public interest in the insect has grown since it was first identified in California in 1990.
The insects may also be called glassy wing sharpshooters, or just sharpshooters. Formally, the glassy-winged sharpshooter is known as Homalodisca coagulata. The insects are around a half inch (12 millimeters) in length, with dark brown to black bodies marked with large creamy white spots. The common name for the insect comes from its transparent wings, which do look a bit like very thin glass. The range of glassy-winged sharpshooters in the Southeast is fairly extensive, and it is believed that the insects caught a ride to California in crops exported from the South.
In addition to Pierce's disease, glassy-winged sharpshooters can carry an assortment of other fungi and bacteria. They are ideal vectors of disease transmission because they are so voracious, consuming many times their own weight in a day. As a result, they may travel far afield, contaminating fresh crops with bacterial infections from other regions. In 1990, the glassy-winged sharpshooter was identified as the culprit behind Pierce's disease infection in Southern California, and the insects have been working their way north.
Pierce's disease is an infection caused by the Xylella fastidiosa bacteria. It infects the xylem of plants, which is the structure responsible for transmission of water and nutrients. Within a year of infection, the infected plant has withered and died, and it must be destroyed, because there is no cure for Pierce's disease. This puts the grape industry at serious risk, and since grapes and wine are major exports of California, several state organizations have joined forces to fight the glassy-winged sharpshooter, using a variety of techniques.
Identification is perhaps one of the most important techniques. Many biologists set out traps around the state to catch insects for later identification. This can provide information about ambient insect populations and their life cycles, and it can be an early warning system for glassy-winged sharpshooter invasions. Many biologists also work directly with farmers, in the hopes of coming up with innovative techniques for countering the threat.
