A Mediterranean fruit fly infestation in the Spring Valley area of San Diego County, Calif., has been eradicated, ending a quarantine that began in late 2008.

“Fruit flies are dangerous pests for California farming and backyard gardens,” said California Department of Food and Agriculture (CDFA) Secretary A.G. Kawamura. “I would like to thank the residents of San Diego County who helped us eradicate this infestation by cooperating with the quarantine.”

Separate Medfly quarantines remain in effect in the nearby Mira Mesa area, as well as farther south in the Imperial Beach area of San Diego County.

The 93-square-mile Spring Valley quarantine was declared after the detection of three wild Medflies in local traps in November 2008.

To eradicate the pest, agricultural officials employed weekly aerial releases of approximately 2.8 million sterile Medflies over an 11.2 square-mile zone at the core of the quarantine area.

Fertile female flies in the environment mate with the sterile male flies but produce no offspring, ultimately resulting in eradication of the pest.

The sterile Medflies were brought in from the joint CDFA-U.S. Department of Agriculture rearing facility in Los Alamitos, which prepares hundreds of millions of sterile flies weekly for release over the Los Angeles Basin.

The Mediterranean fruit fly is one of many pests that threaten agriculture and residential gardens in California. As travel and commerce increase worldwide, the variety and frequency of pests breaching our border are also on the rise.

The pest can infest over 260 types of fruits and vegetables, threatening California’s crops and exports as well as our urban and suburban landscaping and gardens.

A permanent infestation would result in estimated annual losses of $1.3 billion to $1.8 billion.