Risks Seen in Decision Not to Spray for Medflies : Agriculture: Officials don’t want to ‘jump the gun’ after find, but some experts fear an outbreak.

The decision not to begin malathion spraying in San Bernardino County, despite the discovery of two Mediterranean fruit flies there earlier this month, is a potentially risky move that bends established guidelines on eradication of the pest, agriculture officials said Friday.

“There’s risk in anything, but I don’t think it’s that risky,” said Roy Cunningham, a USDA entomologist and chairman of the state’s science advisory panel on the Medfly. “We can’t jump the gun on this thing.”

“It’s a real risk,” said Richard Rice, a UC Davis entomologist who also serves on the advisory panel. “My concern is that if we don’t respond now, we’re going to deal with it on a larger scale next spring.”

Jim Reynolds, western regional director for the U.S. Department of Agriculture, said the latest discoveries were in two intensely monitored areas and were probably isolated finds that pose no immediate threat.

“The bottom line is that it’s not clear what we’ve got,” Reynolds said. “Obviously, we don’t want to play games with this because it could be a costly decision. But at this point in time, we don’t have enough information to say there is a breeding population.”

In previous eradication campaigns, malathion spraying has been ordered whenever two Medflies were found within three miles of each other--a criterion that the San Bernardino finds fulfill.

But officials have decided on a more “flexible” approach, according to Reynolds, because no other flies have been found, and because they worry about waging another long, costly and controversial eradication campaign.

“Those are just guidelines,” Reynolds said of the three-mile standard. “You’ve got to weigh all the factors.”

While residents in the affected area will be spared the rumbling flights of malathion helicopters for the time being, some of the state’s scientific advisers are questioning whether the “wait-and-see” approach is courting a larger and more intense outbreak later.

Rice said the discovery of the two latest female flies in virtually the same area infested earlier this year supports contentions that the Medfly is entrenched in Southern California and continues to survive despite official claims of eradication.

“It suggests to me that we haven’t eradicated the Medfly,” Rice said. “I’d rather see us take a stronger approach and really clean this thing out.”

The two Medflies were discovered Nov. 15 in Rancho Cucamonga and Upland, a week after local, state and federal agriculture officials had jubilantly declared victory in their 16-month, $52-million war against the Medfly. The campaign was the largest ever waged in Southern California.

Cunningham said the latest finds pose a quandary for them.

Doing nothing now could open the possibility of a Medfly population explosion in the spring. But launching an eradication program now, in the winter, when the life span of the Medfly can reach up to four months--compared to three weeks in warmer weather--would require malathion spraying and sterile fly releases at least until May.

“An eradication program now would have to be one of these long, drawn-out winter programs. There’s a tremendous cost,” Cunningham said. “Of course, no one wants to do that.”

Cunningham said he supports delaying such a program, at least for the moment.

Reynolds, of the USDA, said Friday that a survey of traps in the same area this week failed to turn up any new Medflies, bolstering his belief in the wait-and-see strategy.

“Considering the information we have now, I have no concern,” he said. “But if another one is found, that would certainly change things.”