Medfly Flight Plan Shifted to Avoid Air Traffic

State agricultural officials will stop releasing sterile male Mediterranean fruit flies over the San Fernando Valley on weekends to avoid a conflict with air traffic at Van Nuys Airport, it was announced Tuesday.

The pattern flown by the U.S. Department of Agriculture plane from which sterile flies are dropped crosses the approach routes used by aircraft landing at Van Nuys Airport, said Gary Agosta, an entomologist with the state Department of Food and Agriculture.

Both aerial and ground release of the sterile flies are being changed to weekdays from the original Friday-through-Tuesday schedule to avoid the heaviest traffic days at the airport, Agosta said.

Airport officials could not be reached for comment on whether air traffic at the facility was disrupted last weekend. But Agosta said some private pilots reported they had trouble seeing the Medfly plane, a twin-engine Beechcraft.

The airport had 1,558 takeoffs and landings on Saturday and 1,803 on Sunday, heavier traffic than the average for July of 1,375 per day, an airport spokeswoman said. The airport’s traffic is usually--but not always--heavier on weekends than on weekdays, she said.

Officials have released 38 million sterile male Medflies so far in an attempt to end the Valley’s infestation of the crop-destroying pest. The hope is that wild females will mate only with sterile males and fail to reproduce.

Authorities plan to release from 100 million to 300 million sterile Medflies by the end of September in the second phase of the Medfly assault, which began last month with the aerial spraying of the pesticide malathion on 16 square miles of the Northridge-Reseda area.

In another development, agriculture officials were baffled by the discovery Friday of about 100 sterile flies in a trap about three miles outside the 62-square-mile release area, Agosta said.

Agosta did not know how such a large number of flies could be caught outside the release zone but said “it has no significance at all� in the state’s effort against the Medfly.