Medfly Quarantine Is Imposed on Parts of Ventura County : Agriculture: Affected are parts of Camarillo, Somis, Moorpark and Thousand Oaks. The order could last for up to six months.

A quarantine on agriculture susceptible to Medflies was imposed for the first time Wednesday in Ventura County, encompassing 86 square miles of fields and homes within a 4.5-mile radius of the site where two fertile flies were found last week.

The action, which has been expected since two mated female Mediterranean fruit flies were found in eastern Camarillo on Friday, came as inspectors confirmed Wednesday that an additional 10 flies were found in a grove at St. John’s Seminary.

The quarantine boundaries overlap parts of Camarillo, Somis, Moorpark and Thousand Oaks. The lines were drawn by local, state and federal officials after days of mapping and negotiations.

The quarantine will be imposed through at least three life-cycles of the Mediterranean fruit fly, which in the cool fall weather could be up to six months. The quarantine could be extended indefinitely until the pest is wiped out.

It establishes a protocol for treatment with malathion and other steps that commercial growers must follow before they can ship host fruit or vegetables from within the infested area, which includes 40,000 acres of farmland.

Susceptible to the pest are lemons, oranges, grapefruit, avocados, peppers, tomatoes and strawberries.

“I have an avocado crop to pick within a month, so I’ll have to spray them or let them drop,” said grower George Sorich, whose grove falls within the quarantine area. “But the main concern here is that we have to get rid of the fly.”

Residents within the quarantine area are asked not to move any home-grown produce outside the area unless it has been cooked or canned.

The discovery of the latest 10 male flies brought the total count to 53 flies--51 wild males and two fertile females--all found within a quarter mile of the original site.

The quarantine order came from California Agriculture Secretary Henry Voss, with the U.S. Department of Food and Agriculture expected to issue a federal quarantine with identical boundaries.

Officials are still trying to determine the extent of the infestation and will not decide whether to use aerial spraying or other eradication methods until they know whether the infestation has spread, and how far.

“A lot of folks are asking us why we don’t jump in now with a treatment program,” said Doug Hendrix, a spokesman with the Cooperative Medfly Project in Los Angeles, which includes experts from the federal and state agriculture departments. “But we can make that decision much better once we have all the facts.”

The Medfly project, which has overseen the efforts to eradicate the Medfly from the Los Angeles Basin and elsewhere in Southern California, will make recommendations for treating the infestation to Gov. Pete Wilson.

It would take an order from the governor to begin aerial spraying, said Sean Walsh, a Wilson spokesman.

“The Medfly project team are experts,” he said. “And we expect that we are going to take their advice.”

Meanwhile, inspectors have sprayed a combination of malathion and bait on the ground within the half-mile core area of the Medfly finds. In addition, they have set more than 700 traps within the quarantine area to trap the pests.

In a declaration of emergency by Ventura County Sheriff Larry Carpenter on Tuesday, Ventura County agriculture officials estimated potential losses at up to $439 million, which represents the total value of all crops considered to be hosts to the Medfly.

The California Office of Emergency Services recommended Wednesday that Wilson approve a state of emergency, which would clear the way for state disaster assistance, Ventura County disaster officials said.

Times correspondent Julie Fields contributed to this story.