Grapevine-killing pest found at four county homes

June 08, 2001|By KELLY GRANT, Staff Writer

SALTON SEA BEACH — Agriculture officials are keeping a close eye on the northern part of Imperial County after a disease-carrying insect potentially fatal to grapevines was discovered on four residential properties in this area.

Though the half-inch long glassy-winged sharpshooter can carry Pierce's disease, a fatal grapevine affliction, Pierce's has not been found in Imperial County, said Steve Birdsall, county agricultural commissioner.

"We're concerned about this, obviously," Birdsall said. "We're taking it very seriously."

However, Birdsall cautioned there's no reason to panic.

"By itself, (the sharpshooter) is not a real significant pest," Birdsall said.

The California Department of Food and Agriculture reported on its Web site ( that 10 early-stage glassy-winged sharpshooter nymphs were found on a lemon tree in Salton Sea Beach.

Confirmed findings of the sharpshooter were made at four properties in the area, according to the site.

As Birdsall explained, Pierce's disease is often found in citrus trees, where it does no harm. Citrus is the preferred host of the glassy-winged sharpshooter, although the insect sometimes moves to grape vines and carries the Pierce's disease-causing bacterium with it.


An infestation of Pierce's disease in Temecula has resulted in a "significant grapevine die-off," Birdsall said.

The Imperial County area where the insects were found is "quite a ways away from our agricultural production area," Birdsall said.

The closest Imperial County agricultural areas are about 20 miles from where the insects were found, Birdsall said.

Imperial County has a small amount of table grapes growing in the northern part of the county, Birdsall said.

"We're surveying (for the insect) extensively," Birdsall said.

The pest can be eradicated with a "common, low-human toxicity" pesticide, Birdsall said.

One strategy Imperial County officials considered to deal with the glassy-winged sharpshooter is to use the pesticide on the affected properties, Birdsall said.

Birdsall said while this would get rid of the current sharpshooters, more will come down from neighboring Riverside County, which isn't planning any eradication attempts.

Nature may take care of the insects itself. Birdsall isn't convinced the glassy-winged sharpshooter can survive the summer here.

Birdsall said that while he's not certain, "We suspect the climate may have something to do with its life cycle."

The insect has been in the Coachella area for some time, Birdsall said, but as far as he knows, Pierce's disease has not been found there.

According to the CDFA Web site, seven Southern California counties, including San Diego and Riverside, are infested with the pest while most others are considered at-risk.

Staff Writer Kelly Grant can be reached at 337-3441.

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