Crop-Destroying Oriental Flies Found in County

Special poison bait and extra traps were set in an eight-square-mile area near Laguna Beach on Thursday after agricultural officials found three Oriental fruit flies.

The crop-destroying flies were trapped in the south county last week--one on Friday in a backyard orange tree in South Laguna and two Monday in a Laguna Beach loquat tree.

The Oriental fruit fly is distantly related to the Mediterranean fruit fly that devastated crops in Northern California in 1981; the Oriental variety, however, is considered less dangerous.

While only three of the pests were found, agriculture officials expressed alarm. “If we get an infestation here, it could affect the whole state,” Orange County Deputy Agricultural Commissioner Wayne Appel said.

He pointed out that the fly was a potential threat to 236 fruit, nut and vegetable crops, which add up to almost $40 million of the county’s total $254-million annual commercial crop. None of the three insects discovered in the county was found in a commercial crop.

Oriental fruit flies “can cause enormous damage,” said Gera Curry, spokeswoman for the state Department of Food and Agriculture, which is conducting the trapping and eradication program. More than $2.4 billion of the state’s $14-billion agricultural industry is vulnerable to the fly, she said. “That’s why we get excited and move so fast to eradicate them.”

The Oriental fly burrows under the skin of fruit and lays eggs. The hatching maggots destroy the crop.

Curry said it is possible that the flies came from an illegal shipment of fruit from Hawaii. In 1986, postal workers in Costa Mesa intercepted several fruit packages illegally mailed from Hawaii and found more than 170 live Oriental fruit flies, she recalled.

Most Produce Banned

“We definitely see a connection,” she said. State and federal statutes bar importing fruits and vegetables from Hawaii--with the exception of pineapples and bananas--unless the produce has been cleared by agricultural officials, Curry said.

She added that in 1985, the state spent $324,000 to combat infestations of the Oriental fly in Orange and Los Angeles counties.

The discovery of the Oriental flies was the first in Orange County since one was trapped in Anaheim in September, 1986. In that case, no more insects were captured. The largest previous concentration in the county was in 1980, when five flies were found in the Yorba Linda and Fullerton area.

Ordinarily, Appel said, five traps--small cardboard devices containing a scent similar to that emitted by female flies, along with a gummy substance to catch the fly--are maintained in each square mile of the county as a monitoring system.

On Thursday, 45 more traps per square mile, along with special poison bait, were put out in a nine-square-mile area from Laguna Beach to the Salt Creek golf course, Appel said. About 600 poison bait stations were also set up in the area.

No Danger to Humans, Pets

The poison, which consists of an attractant called methyl eugenol and the commercial pesticide Dibrom, is squirted by a hand sprayer in small quantities high up on utility poles and fence posts, at least eight feet above the ground. The molasseslike poison looks black when sprayed on wood, Appel said, and poses no threat to humans or pets. It gradually turns pinkish-gray and loses its effectiveness after a week.

Appel said the poison baiting and expanded trapping program will continue for about three months--the equivalent of three generations of the flies--with poison bait resprayed every two weeks. “If we don’t find any flies in the next three months, we’ll declare the area cleaned up,” he said.