Spring is here and the time has come to begin the glassy-winged sharpshooter (GWSS) trapping, surveying, treatment and bio-control program in Fresno County. The treatment strategy will continue as a suppression effort beginning at the perimeter of known GWSS finds in 2011 and moving inward toward the core of the cities of Fresno and Clovis.
The goal is to stop the expansion of this destructive pest through effective treatments and the use of bio-control measures; while reducing the size of the infested area over time. The result will minimize the impact of this pest to ornamental landscapes and as a serious threat to agriculture. The GWSS causes severe damage by feeding on a wide variety of ornamentals and crop plants. It prefers to feed on stems rather than leaves, using their strong sucking mouthparts to remove fluid and nutrients from plants. As a result of their feeding, they can transmit various plant diseases including Pierce’s disease caused by Xylella fastidiosa.
(For more, see: Fused genes tackle deadly Pierce’s disease in grapevines)
This disease kills grapevines and there are no effective treatments for it. The GWSS adult, a large insect is approximately half-inch long and is dark brown to black, with lighter underside. The wings are partly transparent with reddish veins. When the adults and nymphs are newly emerged, they are grayish to light brown in appearance. The nymphs do not have fully developed wings.
Beginning Feb. 23, homeowners have been asked permission to treat properties, as well as the soil beneath “backyard citrus” (a known prime overwintering host), for the GWSS. Treatment will begin on March 1, 2012 with the application of a systemic insecticide in one or more of the following ways:
1. to the soil directly beneath host plants;
2. sprayed onto the foliage of the plants on properties where the GWSS had been found last season; and/or
3. at the edge of determined quarantine boundaries.
Trapping with yellow sticky panels will commence on May 1, 2012. As done in previous years, traps will be placed in nurseries, commercial citrus orchards and in towns throughout Fresno County. In addition, traps will now be placed in Fresno around the perimeter of the city, the eastern edge of Clovis and surrounding the Sunnyside area at a density of 15 traps per square mile.
The 2012 strategy is for a higher concentration of detection traps to be placed at the edge of the quarantine boundary instead of traps being placed throughout the city. Bio-control efforts will continue through the release of a very tiny wasp that is a parasitoid of GWSS eggs. Areas identified as “good candidates” for bio-control efforts will occur through consultation with the California Department of Food and Agriculture and the Fresno County Department of Agriculture’s Entomologist.
Each Fresno County Department of Agriculture employee has been issued an identification badge and directed to wear it while on duty. Residents and growers are encouraged to ask for official identification badges carried by permanent and seasonal staff employees.
If you think that you have found GWSS or have questions about our trapping, surveying, host treatments or parasitoid release efforts, please call the Fresno County Department of Agriculture at (559) 600-7510. You may also bring a suspect insect to the Department’s Entomologist located at 1730 S. Maple Ave., in Fresno, Monday — Friday, between the hours of 8 a.m. — 5 p.m. for identification.