The quarantine on 65 acres around West Covina last week makes it a misdemeanor for anyone to transport out of the area fruit or any other produce from a tree.
Although the Oriental fruit fly infestation appears to be limited to a few homes in the Woodside Village area of West Covina, fruit transport has been restricted to keep the infestation from spreading, said Bob Atkins, deputy agricultural commissioner in charge of pest prevention.
Stripping fruit off the trees or heavy insecticide spraying, however, will take place only where inspectors have strong evidence that fly larvae are present, he said.
Fruit-bearing plants from retail and wholesale nurseries also will be affected: nursery staff must comply with county guidelines and abatement orders.
The quarantine area covers portions of West Covina, Baldwin Park, Covina, City of Industry, La Habra Heights, La Puente, Pomona, San Dimas and Walnut.
The boundaries are roughly: San Bernardino Road on the north; 57 Freeway and Diamond Bar Boulevard on the east; 7th Avenue and Sunset Avenues on the west, and a line from the intersection of Diamond Bar Boulevard and Brea Canyon Road to Skyline Drive, on the south.
Atkins said the quarantine does not mean that fruit in the area is inedible.
Volume Means Risk
"We just don't want the movement of home-grown produce out of the area," he said. "This is the fruit season. When it's ripe, there's too much for one household to eat. People share. If any of that fruit was infested, you'd run the risk of moving it beyond the infestation area."
The quarantine will last for at least 90 days after the last fly trapping, Atkins said.
A dozen flies were found last weekend on the same properties where flies were trapped and initial eradication treatments began earlier this month, leading inspectors to believe that the earlier treatment was ineffective.
That initial treatment used the "male annihilation method." About 600 blobs of insecticide scented with a sexual lure to attract male flies were sprayed on trees, utility poles and street signs in the affected neighborhoods.
This method kills only adult flies, and would not affect larvae already in the fruit, Atkins said.
In this second stage of treatment, all fruit in the immediate vicinity of homes where the new flies were found last weekend will be stripped, and the plants will be sprayed with malathion or diazinon to kill any larvae. The male annihilation approach will continue in the Woodside Village area.
"It will only be on that property and adjacent ones," Atkins said, referring to the pesticide spraying and stripping. "We believe that one of the properties is responsible for all of the flies."
Unlike infestations of the Mediterranean fruit fly, which can involve aerial spraying of malathion or the introduction of sterile male insects, Oriental fly infestations are handled with relative ease, said Gera Curry, spokeswoman for the state Department of Food and Agriculture.
The Oriental fruit fly attacks more than 230 kinds of fruits and vegetables, making the insect a serious threat to the state's $15.5-billion agriculture industry, she said.