Backyard Orchard News
Bed Bugs at the Bohart
Bed Bugs at the Bohart? Indeed. Those attending the Bohart Museum of Entomology's open house on...
The arm of Danielle Wishon and her bedbugs, feeding.
Close-up of a bedbug in the process of ingesting a blood meal. (Photo courtesy of the Centers for Disease Control for Prevention, image by Piotr Naskrecki)
A She-Bee on the Hebe
The yellow-faced bumble bee, Bombus vosnesenskii, is back. We spotted some overwintering...
Queen bumble bee nectaring a hebe at the Berkeley marina. (Photo by Kathy Keatley Garvey)
Queen bumble bee is aglow in the afternoon sun. (Photo by Kathy Keatley Garvey)
Distinguishing yellow stripe on the lower abdomen is barely visible. (Photo by Kathy Keatley Garvey)
Glassy winged sharpshooter a continuing threat to grape industry
Anaheim boasted a thriving wine industry in the late 1800s, before an unnamed affliction killed 40,000 acres of the grapevines and put 50 wineries out of business. The problem was later found to have been Pierce’s disease of grapevines. Would Anaheim be wine country today if it weren’t for Pierce’s disease? Probably not, but the sad fate of this Southern California wine industry underscores the importance of controlling the disease and the insects that spread it in California’s thriving grape growing regions.
GWSS has turned out to be a very efficient vector of Xyella fastidiosa, the bacterium that causes Pierce’s disease in grapes. When GWSS made their way to places where scientists believed the bacterium didn’t exist, such as Kern County, grapevines began to express symptoms of the disease. The county agricultural commissioners in the San Joaquin Valley have been working tirelessly over the last 10 years to keep glassy-winged sharpshooters out of grape growing regions to protect a very valuable economic driver. In Fresno County alone, where grapes are the No. 1 agricultural commodity, the crop was worth $961 million in 2011.
Despite the efforts to contain GWSS in Fresno County, the pest is spreading very gradually south and east of the Fresno-Clovis metropolitan area into commercial vineyards and orchards.
“Cooperation by urban residents where we find GWSS has been great,” said Fred Rinder of the Fresno County Agricultural Commissioner’s office. Nevertheless, in 2012, GWSS was found spreading out in Kerman, Parlier, Sanger and Kingsburg.
Stephen Vasquez, UC Cooperative Extension advisor in Fresno County, fears local grape farmers have become complacent about glassy-winged sharpshooter and Pierce’s disease, even though all grapes are susceptible. The best way to control its spread, he said, is to monitor and manage sharpshooter vectors and remove and replace vines that have tested positive for Xylella fastidiosa.
“Be vigilant. Learn the symptoms and train crews and workers,” Vasquez said. “Pierce’s disease has been around for a long time and GWSS has been here more than a decade, but we still haven’t had that marriage of the two. That is potentially devastating.”
The UC IPM website has extension information on glassy-winged sharpshooter and Pierce’s disease.
Who's Who in the Bemisia Zoo
It's a catchy title: "Unraveling the Complex: Who's Who in the Bemisia Zoo?" Paul de Barro, a...
Silverleaf whitefly (Bemisia tabaci). Photo by Scott Baurer, USDA.
A Sign of Spring: Flowering Apricots
It's a sure sign of spring when the Japanese apricot tree north of Wickson Hall at the University...
Honey bee lands on a Japanese apricot at Wickson Hall, UC Davis. (Photo by Kathy Keatley Garvey)
Wings buzzing, a bee forages in an apricot blossom. (Photo by Kathy Keatley Garvey)
Honey bee with a pollen load. (Photo by Kathy Keatley Garvey)