California fruit growers battle illegal immigrant -- the 'Medfly'

It's springtime in California. Cherry and plum blossoms dazzle the landscape with bright pink and white petals, the forerunners of coming fruit.

Yet these blossoms are viewed with a mix of hope and concern by state and federal agriculture officials, California government officials, and entomologists. The spring crop of fruits and vegetables, which should ripen in the next six weeks, will reveal whether the final battle has been won in a nine-month war against one of the largest insect infestations ever to occur in northern California.

Beginning last summer, huge populations of the Mediterranean fruit fly -- "Medfly," colloquially -- a fast-breeding, resilient insect that infests some 200 fruits and vegetables --sprung up in the San Francisco Bay Area counties of Alameda and Santa Clara. Extermination efforts have been prolonged not only because of the magnitude of the infestation, but also because local officials have prohibited aerial spraying of insecticides.

Now it appears that the California Department of Food and Agriculture (CDFA), which has spearheaded the extermination program, is winning the war against the Medfly. No Medflies or Medfly larvae have been spotted since Jan. 22.

California growers were much relieved March 6 when the US Supreme Court issued a temporary injunction against a Texas ban on 40 fruits and vegetables being imported from anywhere in California. The Texas Department of Agriculture had ordered the quarantine, requiring that California produce be either fumigated or chilled before entering the Lone Star State.

The Supreme Court decision stated that quarantines imposed by the US Department of Agriculture on the two California counties were adequate control measures and that the ban restricted interstate commerce.

"Everyone is relieved about the decision," said Gary Sack, spokesman for the California Farm Bureau Federation. California farmers had been concerned that other states or countries might initiate similar quarantines on California produce if the Texas ban were upheld. "The state's agriculture would have been brought to its knees if the domino effect had happened," Mr. Sack added.

But while farmers and state officials are breathing a bit easier, spring weather and new crops of loquats, citrus, cherries, and apricots could bring new traces of Medflies, whose larvae have lain dormant in the ground this winter.

In an effort to eliminate the flies and their larvae, the CDFA initially developed a three-pronged control effort that included:

1. The weekly release of millions of sterile Medflies to slow the breeding rate.

2. Limited stripping of fruit from of trees in infested areas.

3. Limited ground spraying with insecticides (principally malathion).

These procedures successfully eliminated Medfly invasions in California in 1975 and last summer in southern California's San Fernando Valley. Infestations have been relatively rare, and this is attributed to stringent inspections at state borders and restrictions on fruit being imported by overseas travelers. State officials feel that infestations generally result from travelers illegally bringing in exotic fruits from out of state.

The Medfly invasion in northern California had grown too large, however, to be effectively controlled by the usual limited measures.

Consequently, in January, fruit-stripping and spraying efforts were intensified. California Conservation Corps workers stripped some 2,500 tons of fruit in a 43.5 square mile area within the two countries. Yet citizens and local officials balked at federal and state proposals to spray malathion from the air. Even though such spraying had effectively stopped previous invasions in Texas and florida, officials were concerned about uncertain health effects from malathion.

Even without the aerial spraying, the $14 million Medfly eradication plan seems to have been effective. "We are cautiously optimistic," says CDFA spokesman George Farnham. "There is only a small likelihood of aerial spraying."

March and April are the critical months, says Dr. Isi Siddiqui, chief of the CDFA's Emergency and Special Projects Unit. the Medfly Technical Review Committee, a group of scientists and agriculture officials from across the US, has set april 15 as a tentative deadline for determining the extent of the Medfly threat. If by that date flies or larvae are spotted, the committee feels that aerial malathion spraying should be seriously considered.

Renewed efforts are under way, however, to prohibit spraying. The Sunnyvale City council in Santa Clara County has passed an emergency ordinance banning such spraying unless public hearings are held. other city councils in the two counties are expected to pass similar bans.

CDFA officials are planning a counterattack against the ordinances. "We plan to go into court to strike these ordinances down," said Jerry Scribner, deputy director of the CDFA and director of the Medfly eradication project. Mr. Scribner does not anticipate that aerial spraying will be required. Yet, he said, "we want to get any legal challenges disposed of and all planning done ahead of time."

Although the controversy surrounding aerial insecticide spraying has yet to be settled, the Medfly infestation in northern California has prompted new efforts to prevent or curtail future pest invasions:

* An increased number of "trappings" --the setting out of traps designed to attract and capture agricultural pests for identification purposes -- throughout the state.

* The California Legislature is considering a bill that would extend the number of trappings to 32,000 throughout California. CDFA officials are optimistic that it will pass.

* Larger populations of sterile flies are being cultivated for ready availability if future infestations occur.

At present, CDFA officials, California growers, and residents of Alameda and Santa Clara counties are hopeful that this spring's fruit crop will go into s upermarkets rather than into plastic disposal bags.