New Spraying Plan Is Unveiled : Medfly: Malathion treatment will continue in much of area now affected by infestation. New outbreaks will also face weekly applications of pesticide.

State agriculture officials, girding for a crucial stage in their long campaign in Southern California against the Mediterranean fruit fly, unveiled details Monday of a new battle plan that calls for continued pesticide spraying over much of the now-infested territory and more aggressive attacks against any new flare-ups.

Under the new plan, roughly 250 of the 470 square miles now being treated with the pesticide malathion will be sprayed from one to three more times this month. For some sectors, spraying will be repeated each week through June. Any new outbreaks also will face weekly aerial applications of the pesticide.

At the same time, the strategy calls for less reliance on sterile fruit flies, which were to have replaced the controversial malathion-bearing helicopters as the eradicators’ principal weapon.

Under the new scenario, most spraying will be finished by the end of May--if no new flies are found. Officials, who initially had hoped to end all spraying by Wednesday, were reluctant to address the prospects of new outbreaks.

San Bernardino, and Woodcrest in Riverside County, will continue to be sprayed after May.

Among communities to receive their final sprayings this month and then be treated with the release of sterile flies are Burbank, Hancock Park, Walnut, Diamond Bar, Pomona, San Dimas, Glendora, Irwindale, Azusa, Bradbury, Brea and La Habra.

Among communities to receive their final spraying this month and require no further treatment are Downey, Norwalk, Artesia, Cerritos, Gardena, Bell, Maywood, Lynwood, Eagle Rock, South Pasadena, Panorama City, Garden Grove, Pasadena, San Marino and Temple City.

Underlying the tactical shift is a widely held assumption that the next few months will prove pivotal in the 10-month-long struggle to eradicate the pest, which is regarded as a menace to the state’s enormous agricultural industry.

“I think the months of May and June will be most critical,” said Isi Siddiqui, assistant director of the state Department of Food and Agriculture.

Summer heat provides ideal breeding conditions for the Medfly. As part of the new plan, eradication efforts will begin any time a single fly is found in a neighborhood. Previously, two flies were required before an infestation was declared.

Siddiqui, who heads the eradication effort, declined to assess how the campaign is going. “We have to find few flies for a few weeks before I can say where we are,” he said.

James R. Carey, one of five scientists advising the state effort, expressed even more pessimism about what the summer might bring.

“It’s clear,” the UC Davis entomologist said. “We are going to find more (flies). It’s not a matter of if, but when.”

The broad outline of the new attack had been revealed Friday when Carey and other science advisers made a series of recommendations to the Department of Food and Agriculture. Henry Voss, who heads the department, had agreed in principle to the new spraying schedules and protocols before their release.

The infestation has grown over the months to about 470 square miles in Los Angeles, Orange, San Bernardino and Riverside counties. The state divides the infestation into 19 zones, stretching from Hancock Park in Los Angeles to Woodcrest.

Monday’s detailed, zone-by-zone schedule of spraying and sterile fly releases shows that about 250 square miles of the spray zone, including Garden Grove, Eagle Rock and Panorama City, will be sprayed up to three more times this month. Most will be sprayed only once more.

Conversely, malathion treatment will end Wednesday over about 225 square miles of Los Angeles and Orange counties, including Glendora, Brea and Upland.

About 170 square miles of infestation will be treated with the release of sterile flies after the spraying ends. A shortage of the steriles, which over the span of three life cycles breed fertile flies out of existence, prevented officials from converting completely to a program of fighting outbreaks with one or two sprayings followed by sterile fly releases.

In addition to more spraying in some areas, 34 square miles in the city of San Bernardino will be repeatedly sprayed with malathion through at least June because of the limited sterile fly supply.

Similarly, Riverside County’s Woodcrest community will be sprayed during the summer, largely because of its commercial citrus groves, which require a stricter eradication procedure.

Siddiqui cautioned that discovery of any new Medflies could force revisions in the plan. During the infestation in Northern California during 1980-82, a relatively quiet spring was followed in June and July with an explosion in the Medfly population. The infestation quickly grew to over 1,300 square miles--still the largest Medfly infestation in the state’s history.

A flurry of fly trappings in Southern California this spring has Siddiqui and other experts nervous that they are a harbinger of a bad summer.

Malathion loses some of its potency in hot weather, forcing the state to spray every seven to 10 days rather than the semimonthly scheduled followed in cooler months.,

The news of more pesticide spraying for some communities was greeted Monday with derision.

“I don’t believe anything they say anymore,” Norwalk City Councilwoman Grace Napolitano said of state officials. “What’s to prevent them from spraying again? It’s asinine. They’ve got to be stopped.”

Even among those who will see their last sprayings this week, the reaction was grim.

“I’d like to say, ‘Great, it’s all over,’ ” said Pasadena City Director William Paparian. “But is it really over? When will it ever be over?”

The panel of scientific advisers met in Los Angeles last week to review the state’s previous plan to phase out most spraying by May 9, which the scientists had opposed as risky and premature.

Voss at the time overruled the panel, believing in March that enough sterile flies would be available from breeding facilities in Hawaii by early May to replace the pesticide applications.

MEDFLY TREATMENTS--Planned spraying areas and areas designated for release of sterile flies. A32

MEDFLY SPRAYING: Map of tonight’s treatment area. B2

THE MEDFLY INFESTATION

More treatments have been scheduled in some Southern California areas in the battle against the Mediterranean fruit fly. Map shows the numbered zones that have received malathion spraying to date, the area that has been treated with the release of sterile flies only, and the Medfly quarantine areas.

Text below details the status of each area, including plans announced Monday for future spraying and release of sterile flies. 1. Brea / La Habra: Previously sprayed nine times. Last treatment was April 30. Sterile flies scheduled to be released this week. 2. Downey / Norwalk: Previously sprayed nine times. One additional malathion treatment scheduled for Monday. 3. Eagle Rock / South Pasadena: Previously sprayed nine times. Two additional malathion treatments scheduled for tonight and May 17. 4. Glendora: Previously sprayed seven times. Last treatment was April 30. Sterile flies scheduled to be released this week. 5. North Hollywood: Previously sprayed eight times. Last treatment was April 28. 6. Panorama City: Previously sprayed seven times. Two additional malathion treatments scheduled for May 16 and 23. 7. Rosemead / Monrovia: Previously sprayed 10 times. One additional malathion treatment scheduled for Wednesday night. 8. South Gate: Previously sprayed nine times. One additional malathion treatment scheduled forMay 15. 9. Sylmar: Previously sprayed five times. Last malathion treatment was April 2. 10. Irwindale: Previously sprayed six times. Last malathion treatment was April 30. Sterile flies scheduled to be released this week. 11. Verdugo Hills: Previously sprayed five times. Last time sprayed was April 26. Sterile flies scheduled to be released this week. 12. Garden Grove: Previously sprayed six times. Three additional malathion treatments scheduled for May 16, 23 and 30. 13. Pomona: Previously sprayed four times. Fifteen square miles were phased out on May 3. Sterile flies scheduled to be released the week of May 14. An 11-square-mile extension that includes the northern part of Phillips Ranch, the western part of Pomona and all of Puddingstone Reservoir are scheduled for treatment Thursday night. Sterile flies scheduled to be released the week of May 21. 14. Diamond Bar: Previously sprayed two times. Fourteen square miles were phased out on April26. Sterile flies scheduled to be released this week. A 24-square-mile extension that includes most of Walnut, the southeast corner of West Covina and portions of Los Angeles County is scheduled for treatment Thursday night. Sterile flies scheduled to be released the week of May 14. 15. Upland: Previously sprayed two times. Fourteen square miles were phased out on May 4. Sterile flies scheduled to be released the week of May 14. 16. Woodcrest: Previously sprayed two times. Spraying will continue into June. 17. Hancock Park: Previously sprayed two times. Last treatment was May 7. Sterile flies scheduled to be released the week of May 14. 18. San Dimas: Previously sprayed two times. One additional malathion treatment is scheduled for Thursday night. Sterile flies scheduled to be released the week of May 21. 19. San Bernardino: Malathion spraying scheduled to begin Friday night and will continue into June. Compiled by Times editorial researcher Cecilia Rasmussen