The California Department of Food and Agriculture has discovered four wild female Mediterranean fruit flies in two areas in Rancho Palos Verdes and Rolling Hills in Los

Angeles County.

On Oct. 26, crews will begin conducting ground treatments using an organic formulation of the insecticide spinosad within a 200-meter radius of the detections.

On Oct. 27, the state will increase aerial releases of sterile male Medflies by 250,000 sterile flies per square mile. The release area is 12.86 square miles. 

The theory is the sterile males will mate with fertile females, and no eggs will be produced. A female Medfly typically mates only once in her short lifetime.

Rancho Palos Verdes and Rolling Hills are already part of a joint preventive project between the state and the U.S. Department of Agriculture that releases millions of sterile male Medflies each week over the Los Angeles Basin.

The program was introduced in 1996 and has dramatically reduced the number of infestations.

Between 1987 and 1994, an average of 7.5 Medfly infestations were discovered each year in California. Since the preventive program began in 1996, there have been just seven

infestations statewide.

Three of the seven have been detected this year. In addition to the recent Los Angeles County finds, the state is conducting eradication programs in San Jose and near Dixon, about 20 west of Sacramento.

This is the first Medfly infestation in Los Angeles County since 2001, when flies were found in the Hyde Park area. That infestation was successfully eradicated using the same techniques.

A quarantine in the Los Angeles County area is anticipated shortly.

The Medfly can infest more than 260 types of fruits and vegetables, causing severe impacts on California agricultural exports. A permanent infestation would result in estimated annual losses of $1.3 billion to $1.8 billion.