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Aerial Spraying Against Medfly to End by May 9

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TIMES STAFF WRITER

Aerial spraying of the pesticide malathion--a controversial staple of life for many Southern Californians since last summer when a stubborn infestation of Mediterranean fruit flies was first detected--will end in seven weeks, state officials announced Monday.

Henry J. Voss, director of the state Department of Food and Agriculture, set a May 9 deadline for the end of spraying in the 380 square miles of Los Angeles and Orange counties already known to be infested.

Voss said spraying will be phased out through the use of hundreds of millions of sterile fruit flies, which are expected to be available in large quantities when two new breeding facilities in Hawaii become operational in May.

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The flies are used to mate with fertile Medflies with the hope of breeding the pest out of existence. Early in the infestation, before it spread from central Los Angeles to Orange County and the San Fernando Valley, state and county officials had tried to employ sterile flies, but the expanding outbreak quickly consumed available supplies.

Isi Siddiqui, assistant director of the department and the state official directing the eradication effort, said the decision to end the spraying was prompted by lack of new fly discoveries in the past month and assurances that an abundant supply of sterile flies will be available from the new breeding facilities.

“Going without a fly find for four weeks has given us confidence that we’ve licked this,” Siddiqui said. “Our concern was that there wouldn’t be enough sterile flies, but they assure us there will be enough. I feel confident.”

Voss’ announcement came as a surprise. The most optimistic forecast for an end to the malathion treatments had been sometime in June.

In setting the May 9 deadline, Voss went against the recommendation of a panel of scientific advisers, who urged Voss not to jeopardize the progress already made and continue with the spraying to root out the last vestiges of the fruit-destroying pest.

One adviser warned that Voss was needlessly “painting himself into a corner” by promising too much too soon.

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But Siddiqui said Voss believed that aerial spraying should not be prolonged as long as sterile flies were available.

“How could we explain to the public if we had all these sterile flies but continued spraying?” Siddiqui asked.

State officials concede more wild Medflies may be discovered in the coming months. But they are optimistic the new supply of sterile flies will bring an end to the repeated aerial sprayings that have infuriated legions of residents and unleashed a wave of ordinances, lawsuits and legislation to stop the spraying.

“The department is going to make every effort not to go back to multiple spraying,” Siddiqui said. “We feel we are very close to achieving that.”

Until the shipments of sterile flies arrive, Voss said spraying will have to be increased from once every three weeks to once every two weeks because of the warm weather, which make the Medfly more active.

Natalie Bosecker, a spokeswoman for the eradication program, said most areas in the current treatment zone will be sprayed an additional three times, at most.

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In addition, any newly infested areas will have to be sprayed one or two times. But Siddiqui said the state expects to have a sufficient reserve of sterile flies to avoid going beyond that number of spray treatments.

Gov. George Deukmejian had no statement concerning Voss’ deadline. But his press secretary, Bob Gore, said the decision fulfilled a promise that the state has consistently made to the public over the past few months.

“We’ve said all along that we prefer alternatives to spraying. We’ve said all along that a new (sterile fly breeding) facility is being built and Voss has said all along that he expected it to be producing in May,” Gore said. “It’s hardly startling. We’ve been saying it all along, but no one has been listening.”

The five members of the state Medfly Science Advisory Panel, who had recommended last week against an early halt to aerial spraying, were skeptical and voiced concerned about Voss’ announcement.

Roy Cunningham, a U.S. Department of Agriculture entomologist and panel chairman, said breeding sterile flies is a notoriously tricky proposition and trying to double or triple the current level of production could cause problems.

“It frequently happens,” said Cunningham, who is considered by many to be the nation’s top Medfly expert. “You try to up production and quality goes right down.”

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Indeed, there was suspicion that the 1981-82 infestation in Northern California was exacerbated by the release of some fruit flies that were not sterile, significantly expanding the population of fertile flies.

Cunningham warned that poor-quality flies could be too weak to compete for mates with wild flies, making them worthless in an eradication effort. He added that ending the spraying program so close to completion is a needless disruption that could destroy the progress already made.

“We’re just leaving ourselves open,” he said.

Malathion opponents also were hesitant to cheer the end of aerial spraying.

William Paparian, a Pasadena city director who conceived of a novel ordinance to stop the aerial spraying by banning low-flying helicopters, said it was hard to feel comforted by the May 9 deadline after already being sprayed for three months.

“I’m not celebrating,” he said. “It seems they are responding to the complaints, but I’m not satisfied because of these unanswered health questions.”

State Sen. Art Torres (D-Los Angeles) added that while the battle to stop the repeated spraying this year may be over, the war to make sure it doesn’t happen again is not.

Torres, who has been one of the most vocal legislators against spraying, said he believes the outpouring of opposition to malathion spraying succeeded in pressuring Voss to end the state’s aerial campaign.

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“I think he’s running scared because of the tremendous outcry,” Torres said.

But he said he is worried that the state could revert to its strategy of multiple pesticide spraying if another infestation strikes.

“The issue is not going to go away,” he said.

Voss’ plan to phase out aerial spraying hinges on the three sterile fly breeding facilities in Hawaii. Only one of the breeding plants in Honolulu is currently operating. The facility has been producing about 100 million sterile flies a week, according to Nori Tanaka, one of the key entomologists in charge of the program.

Tanaka said construction of a new facility across the street is not completed, but that he was confident it would be producing up to another 150 million sterile flies by May 1.

“I don’t think we’re going to have any problems,” he said. “We will deliver.”

A bigger question mark is the new U.S. Department of Agriculture facility in Waimanalo, Hawaii.

The facility is designed to produce a maximum of 500 million fruit flies a week, although there have been problems with the building’s environmental system, which controls temperature and humidity.

Project director Glenn Hinsdale said he hopes to be shipping about 100 million sterile flies to California by May and gradually increase to 200 million by the beginning of June.

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“I think we can do it,” Hinsdale said, “but breeding flies is something you can’t force.”

Voss also announced Monday a plan to begin a two-year program of saturation trapping in certain areas to resolve a debate started by James R. Carey, an entomology professor at UC Davis, and one of the state’s five scientific advisers in the eradication campaign.

Carey announced at a hearing of the state Assembly two weeks ago that he believed the Medfly has never been completely eradicated and is now deeply established in parts of Northern and Southern California.

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