70 Square Miles in 4-City Area : Quarantine Imposed After Fruit Fly Sightings

State and federal agriculture officials quarantined 70 square miles in San Diego and three adjacent cities Thursday after sightings of Oriental fruit flies--one of the greatest enemies of California produce, officials said.

Kathleen Thuner, San Diego County agricultural commissioner, said produce grown within the enclosed area cannot be removed.

“We have found three flies, two males and one female,” Thuner said. “So far, we’ve been lucky. The flies have only been found in urban areas, away from large areas of produce. Our main concern is that they do not spread.”

The finding of the female fly--with eggs--makes that concern a legitimate one, Thuner said. Female Oriental fruit flies can lay 1,500 eggs in a lifetime--eggs that mature very quickly, she said, adding that adult flies are very active and can fly several miles a day, making containment difficult.

The pest, which originated in Southeast Asia, is considered the second most destructive fly to agriculture--trailing only the Mediterranean fruit fly. It is known to destroy more than 230 fruits and vegetables, including avocados, grapes, lemons, peaches, plums and tomatoes--many of them California’s primary agricultural products.

Though the quarantine limits private growers--people who may have a “peach tree in their backyard”--from moving their produce outside the area, they do not have to destroy their produce, Thuner said.

“As far as I’m concerned, you can eat your fruits, make pies with them, whatever. We just don’t want you to move it out of the enclosed area.”

She said that eating infested fruits or vegetables is not harmful.

Nurseries or other commercial producers must strip their trees and have goods inspected before they can be moved across the enclosed area, Thuner said.

The quarantine, which was issued by the U.S. Department of Agriculture and the California Department of Food and Agriculture, includes sections of North Park, Hillcrest, Grantville, La Mesa, Lemon Grove and National City.

Thuner said it is too early to predict how long the quarantine will last, but it is likely that it will be in effect for at least six months.

With potentially infested fruits and vegetables contained, the county has launched an offensive to rid the area of the pest.

Fruit-bearing trees within 200 yards of the female fly’s sighting--the 900 block of 44th Street--will be sprayed with the pesticide malathion, Thuner said. Nine square miles within the quarantine area will be covered with traps to lure any male flies. She said a combination of the sex lure methyl eugenol and the pesticide naled will be sprayed on trees and telephone polls to kill the males.

This treatment will be administered at least three more times, once every two weeks.

Thuner said San Diego earned the “dubious distinction” of being the first county in California to be attacked by the Oriental fruit fly in 1974. Since then, the pest has returned to the county three times, the most recent in 1983. She said the fly’s debut caused the most inconvenience, forcing a 10-month quarantine.

California’s occasional bouts with the pest can be blamed on its Pacific neighbor Hawaii, said Gera Curry, information officer for the California Department of Food and Agriculture.

“The Oriental fruit fly problem has gotten completely out of control in Hawaii,” she said.

“Our problem begins when tourists returning from Hawaii smuggle uninspected fruit with them,” she said. “Often, these fruits are infested with maggots. Once they get over here, they mature into flies and attack our produce.”

The problem is made worse because tourists often mail infested fruit from Hawaii as well.

“I know of numerous cases in Orange County post offices where they found rotting fruit that were infested with maggots, inside packages,” she said.

Curry said there are laws penalizing smugglers of uninspected produce but such legislation is often ignored.

“People have to realize these laws are not arbitrary,” she said. “Not only is it a major inconvenience to live in a quarantined area, it costs an awful lot to combat these flies.”

Curry said the cost of ridding these pests--which requires many workers to trap and spray each time a quarantine is issued--demands “a bare minimum of $100,000.”