Yet another Mediterranean fruit fly has been found in northern San Diego County, a major avocado and citrus growing region of Southern California. 

The pest, a mated female, was trapped Sept. 9 in Escondido, Calif., according to a California Department of Food and Agriculture news release. 

The agency started releasing more than 2 million sterile flies Sept. 11 in a 9-square-mile area around the Medfly discovery, the release said. Crews also are spraying a bacterial pesticide in a 200 meter radius around the trap.

“By utilizing sterile Medflies, we rely on biology to help us achieve eradication,” A.G. Kawamura, secretary of the Department of Food and Agriculture said in the release. “It’s a great example of the progress that is possible through agricultural research.”

Because the insect can infest more than 260 varieties of fruits and vegetables, the state agency plans to establish an agricultural quarantine in the area, the release said. Residents will be urged not to transport backyard-grown produce outside of the area and to consumer homegrown fruit and vegetables on site.

A joint U.S. Department of Agriculture-California facility in Los Angeles County produces millions of sterile Medflies weekly for release over the Los Angeles basin. The facility provided the sterile flies released in San Diego County, the release said.

The sterile release program has a proven track record of 30 years of success in Southern California, according to the release.