Sterile Medfly Shortage Has State Worried : Infestation: Problem is described as temporary, but adviser says it offers the pest a 'window of opportunity' to breed.

TIMES STAFF WRITER

The state's hopes of eradicating the Mediterranean fruit fly with the release of millions of sterile Medflies has been shaken by a temporary but severe shortage of sterile flies. The situation has agricultural workers scrambling to shore up the beleaguered program and may open what one scientific adviser called a "window of opportunity" for the prolific pest to breed.

The shortfall, which has cut the number of sterile flies expected to be shipped to California by a third, should be corrected by next week, according to state agriculture officials, who insisted it does not pose a long-term problem for the eradication program.

But Richard Rice, one of five entomologists on the state's Medfly Science Advisory Panel, said some areas have had to be treated with far fewer sterile flies than what the panel considers acceptable. That, he suggested, could pose a threat to the eradication program.

"If there are any adult flies out there, all they need is one day to breed," Rice said. "It makes me very nervous."

Meanwhile, the state announced Wednesday that its fleet of malathion spraying helicopters will move out of El Monte Airport this week and set up at Riverside Municipal Airport, where they have occasionally launched in the past.

The state's helicopters have flown out of El Monte since the spraying program began last year. But at the urging of Los Angeles County Supervisor Pete Schabarum, whose district includes El Monte, state officials resolved to find a new takeoff point.

Agriculture officials had planned to use Fullerton Airport to base their helicopters for the last few aerial sprayings in Los Angeles and Orange counties, which are scheduled to end May 30. But their plan was met with protests from Fullerton city officials.

The state's move to Fullerton was blocked Tuesday by a Superior Court commissioner in Santa Ana. Isi Siddiqui, the assistant director of the state Department of Food and Agriculture who heads the eradication program, said the shortfall in sterile flies was caused by delays and production problems at three breeding facilities in Mexico and Hawaii.

The approximately 330 million sterile Medflies the state needs each week to treat the infestation plummeted this week to about 220 million, he said.

Siddiqui said the problems should be solved with the shipment beginning next week of additional sterile flies from Mexico.

The release of sterile flies is the cornerstone of the state's new eradication strategy. Sterile flies are used to disrupt the breeding pattern of wild Medflies. Scientists believe the sterile male flies will mate with fertile females, leading to the eradication of the pest. Previously, the state was forced to repeatedly spray areas with malathion because there were not enough sterile Medflies to treat the entire infestation.

Under pressure to phase out aerial spraying, the state launched a crash program to speed the opening of two new breeding facilities in Hawaii and secure additional sterile fly shipments from Mexico.

Scientific advisers had warned agriculture officials months ago that the delicate process of breeding the flies could break down if the state moved too quickly to boost production.

Rice and other members of the panel, including Chairman Roy Cunningham, have argued against relaxing any of the strict guidelines set up for the sterile fly release program, saying it would be risky considering the size and unpredictability of the Southern California infestation.

"It's very discouraging to find out that we can't do what we say we are going to do," Rice said. "You really feel like we aren't doing the job like it should be done."

Siddiqui said the Mexican facility is expected to begin shipping an additional 80 million sterile flies next week.

Although there will still be a slight shortage of about 20 to 30 million sterile flies, Siddiqui said the program can adjust by distributing the shortfall through the area.

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