Lazy, Pink Medflies to Swarm on the Valley

They will be Day-Glo pink, sterile, “clingy” and even “lazy,” but the millions of male Mediterranean fruit flies to be released starting this week in the central San Fernando Valley will barely be noticed, state agriculture officials said.

The sterile male flies are intended to mate with their produce-destroying female counterparts, halting the Medfly infestation discovered this month. They are dyed pink so they can be distinguished from those Medflies already in the area.

The traces of pink fluorescent dye may not be visible on all the tiny fruit flies, but then again, most Valley residents probably won’t encounter the insects, agriculture officials said.

‘They Won’t Bother You’

“You may see them in trees, but they won’t bother you like a housefly does,” said Dorthea Zadig of the state Department of Food and Agriculture. “They’re lazy.”

The unleashing of the sterile fruit flies represents the second phase of the campaign by state and Los Angeles County officials against the infestation in the Valley, where a 62-square-mile-area was declared quarantined last week. It follows Monday’s aerial spraying of the pesticide malathion in parts of Northridge and Reseda, which some residents complained was hastily organized. Indeed, the spraying was criticized as unnecessary by at least one environmental group, the National Coalition Against the Misuse of Pesticides, which said that state officials should have reversed the order of their assaults, letting loose the sterile flies first.

Nonetheless, state agriculture authorities said they will proceed with plans to free 20 million males this week and follow later with more hordes until the entire sterile fruit fly count in the central Valley reaches 100 million to 300 million.

No Threat to Health

Officials said they will present no health threat to humans. But the flies, scheduled to start being released Tuesday morning from an airplane and from buckets on the back of a roving truck marked “sterile fly release,” might find their way through open doors and windows in the 72-square-mile target area, said spokeswoman Gera Curry.

Although they won’t pester people like houseflies do, they won’t be easily shooed away either, because “they’re clingy,” Curry said. “They have been reared with human beings around.”

Female Medflies normally lay their eggs into fruit and vegetables, which become maggot-infested, unsalable and inedible. But if, as planned, survivors of the malathion spraying unwittingly mate with the sterile males, their eggs will never hatch, fruit will not be destroyed and the infestation will be ended, said William Edwards, chief deputy of the Los Angeles County agricultural commissioner’s office.

The sterile Medfly release will continue for the next two months. County agriculture officials expect their plan to work as well as a similar attack that successfully wiped out an infestation last year in eastern Los Angeles County, Edwards said.

Reared in Hawaii

The sterile flies are raised at a state laboratory in Hawaii, where Medflies are common. The lab was established after the state’s damaging 1981 Medfly infestation, which cost the state $97.6 million in eradication efforts.