Medfly Find in Diamond Bar Rattles Experts : Infestation: State agricultural official says it won’t change commitment to end aerial spraying. But some on science panel call it a disturbing development.

Three days after unveiling plans to conclude aerial malathion spraying over Los Angeles and Orange counties by May 9, agriculture officials glumly announced on Thursday that a fertile Mediterranean fruit fly had been trapped for the first time in Diamond Bar.

Rex Magee, associate director of the state Department of Food and Agriculture, said the discovery will not require aerial spraying--or change the state’s commitment to end spraying in previously infested sectors of Southern California.

The fly was a young, unmated female, reducing somewhat its significance as an indicator of broader infestation.

But some of the state’s five scientific advisers in the eradication program said the Diamond Bar discovery is a disturbing development, potentially representing the first of a new round of outbreaks generated by the warm spring weather.

Roy Cunningham, a U.S. Department of Agriculture entomologist and chairman of the panel, said the discovery confirms his belief that agriculture officials have made a serious mistake in setting an end date for aerial spraying with months of warm weather still ahead.

“I can’t understand why they decided to paint themselves into a corner,” he said. “Seems like they shot themselves in the foot on this one.”

The immature fly was trapped Tuesday in a loquat tree on Evergreen Springs Drive in Diamond Bar, and is the first discovered in Los Angeles and Orange counties since Feb. 13. The fly was found about 2 1/2 miles south of an infested portion of Pomona and three miles east of a Brea infestation. The fly was positively identified by the state laboratory in Sacramento on Wednesday.

Magee said there had been some early signs that Medflies might be expected in Diamond Bar this year. He said Medflies have been found in almost all areas surrounding Whittier, considered the core of the infestation, except Diamond Bar.

“We’ll probably find more,” he said, “but that was anticipated.”

Magee said a single unmated female is not a serious threat by itself. It could be an isolated discovery of a fly carried in by a car or the wind.

But if a mated female Medfly or several more flies were discovered, an infestation would be declared, triggering the state’s standard eradication procedure: one or two aerial malathion treatments, followed by the release of sterile Medflies to breed the pest out of existence.

Agriculture officials want to phase out aerial pesticide spraying as early as possible and replace it with the release of millions of sterile fruit flies. The plan would not apply to new outbreaks, such as the one in Diamond Bar. Those would be treated with a maximum of two sprayings and then the release of sterile flies.

The state’s plan, which was approved by the director of the state Department of Food and Agriculture on Monday, hinges on the completion of a new breeding facility in Hawaii that is expected to ship 150 million sterile fruit flies a week by early May.

Cunningham and other members of the science panel had warned that it is risky to rely on the new facility. The panel argued that it made no sense to abandon spraying so close to the end of an early strategy that called for each infested sector to be sprayed about a dozen times.

He said that under the state’s new plan, outbreaks outside the current treatment zones could drain the supply of sterile flies, threatening the success of the program.

Magee countered that the state is confident it will have enough sterile flies in reserve to treat at least two new infestations and to phase out spraying in currently infested areas by May 9.

“I’ll meet that deadline. I’m going to have sufficient flies,” Magee said. “We’ve got enough to handle it, no problem.”

But if there are many new simultaneous outbreaks, such as happened in December when the state depleted its supply of sterile flies and was forced to rely on repeated malathion spraying, there could be problems, he said.

“Then you’re reaching the capacity of the flies we’ve got again,” Magee said.

Spraying Schedule State agriculture officials this week announced new aerial spraying dates for areas thought to be infested with the Mediterranean fruit fly. These are expected to be the last sprayings. Under an accelerated schedule aimed at ending the controversial eradication effort by May 9, the Southland spray areas will be hit every 14 days beginning in April. Here are the Orange County areas affected and the dates of spraying: Brea: (An eight-square mile area that includes parts of Brea, La Habra and Fullerton): Monday April 16 and April 30 Garden Grove: (A 36-square-mile area that includes virtually all of Garden Grove, about half of Westminster and parts of Anaheim, Orange, Santa Ana, Huntington Beach, Cypress, Los Alamitos and Stanton): Thursday, April 19 and May 3