More glassy-winged sharpshooters found in Marin, Sonoma

Agricultural pest inspectors in Sonoma and Marin counties found a greatly feared nemesis for North Coast winegrape vines, as well as for other plants, on nursery shipments from Southern California.

During routine inspections of shipments from Santa Barbara and Ventura counties, nymph glassy-winged sharpshooters (ipm.ucdavis.edu/PMG/PESTNOTES/pn7492.html) were captured on Sept. 29 in Marin and Sept. 30 in Sonoma, the agricultural commissioner offices of both counties reported Oct. 8. A viable egg mass was also found on the Sonoma County shipment.

The insect sucks the fluids out of a wide variety of plants and spreads lethal diseases to crops such as almonds and grapes. There are no known cures for these ailments, such as Pierce's disease in vines. Glassy-winged sharpshooters are known to feed on more than 300 varieties of plants, including widely used landscape plants, fruits and vegetables.

“Protecting agriculture and the environment from this serious pest is one of our top priorities,” said Stacey Carlsen, Marin agricultural commissioner. “If the glassy-winged sharpshooter were to get established in the North Bay, the potential damage to the wine grape industry, landscape plants and the environment is significant.”

An adult glassy-winged sharpshooter can drain 200 to 300 times its bodyweight in water every day, the equivalent of a 150-pound adult drinking about 4,300 gallons of water per day. A tree heavily infested with the insect can lose up to 10 to 15 gallons of fluids per day, requiring a significant increase in irrigation to keep plants healthy.

“This is especially concerning when we remain in a serious drought,” Carlsen said.

The adult specimens were hand-delivered to the California Department of Food and Agriculture entomology laboratory, where they were officially identified. All plants in the shipments from Santa Barbara and Ventura counties were returned to sender.

Local nurseries are cooperative in notifying county agriculture departments about plant material received from areas infested with glassy-winged sharpshooters, according to the ag commissioners.

The nurseries that received the plant shipments were purposely not disclosed to protect them from unwanted attention, officials said.

Contacts for reporting glassy-winged sharpshooter finds:

Marin County Agricultural Commissioner's Office, 415-473-6700, marincounty.org/depts/ag

Marin County Farm Adviser, University of California Cooperative Extension, 415-473-4204, 1682 Novato Blvd., Novato

Sonoma County Agricultural Commissioner's Office, 707-565-2371, sonomacounty.ca.gov/Agriculture-Weights-and-Measures

Sonoma County Farm Adviser, U.C. Cooperative Extension, 707-565-2621, cesonoma.ucanr.edu