San Francisco — The lid on the California fruit and vegetable basket -- the nation's largest -- hasn't slammed shut yet, and probably won't. Families in Boston, Minneapolis, St. Louis, and most other places around the United States still can dine on fresh avocadoes, oranges, tomatoes, and other produce from this state.
In most states no slowdown in delivery of produce from California is likely to be apparent. Some 200 fruits, nuts, and vegetables grown in the state -- 20 of them widely distributed in the US -- can be "hosts" for the Mediterranean fruit fly, which now infests three Bay Area counties.
US Secretary of Agriculture John R. Block was optimistic in a national television appearance July 19 -- and so are most officials and expert observers here -- about the effort to eradicate the "Medfly" in the relatively small infested area.
By noon on July 20, helicopters had completed the first spraying of the infested area with "baited" droplets containing a solution of malathion pesticide and a protein syrup. The spraying zone has grown from 97 square mile to 227 square miles and includes parts of Alameda, Santa Clara, and San Mateo counties.
No ill effects on the populace of the thickly settled Palo Alto-San Jose area had been reported, and most concern was centered on whether the Medfly could be stopped before spreading into major agricultural areas -- particularly the Central Valley.
Over objections by Secretary Block, 12 Southern states plus Colorado imposed restrictions on shipment and sale of California produce.
But on Monday a federal court judge in Texas -- which had banned all but fumigated produce from California -- issued a restraining order setting aside the Texas ban pending a July 25 hearing.
Fumigation is a slow, costly process at best, and California farmers don't have nearly enough facilities to fumigate the greater part of fruits and vegetables normally shipped out of state.
In addition to Colorado and Texas, states with some form of restriction on California fruits and vegetables include Alabama, Arkansas, Florida, Georgia, Kentucky, Louisiana, Oklahoma, North Carolina, South Carolina, Tennessee, and Virginia.
With the political implications of the Medfly situation out of the spotlight at least for a time, and with a sharp drop in concern over possible harmful effects of malathion, Californians began to assess the economic impact of the Medfly problem.
Since June 1980, when medflies were first discovered in the south San Francisco Bay area, the state has spent some $22 million to fight the pesky insect. Hopes that eradication efforts last winter (without aerial spraying) had succeeded were dashed June 26 when a maggot was found in an apricot by a Santa Clara County resident.
Thus began the controversy that ended with Gov. Edmund G. Brown Jr. giving in to federal pressure and ordering that malathion spraying start on July 6.
The governor has estimated that the current Medfly campaign will cost no less than $33 million, and some sources estimate that $50 million has spent since June 26.
Besides aerial spraying, the program involves ground-level spraying, stripping fruit from trees and destroying it, enforcing a quarantine against taking fruit out of the infested area, releasing sterile male fruit flies, and setting up thousands of traps across the state to detect flies that spread into new areas.
As the new fight against the Medfly began, there was less than $3 million in state funds specifically appropriated for fruit fly control.
Secretary Block said the federal government would pay 50 percent of the cost of aerial spraying, but so far there is no indication the Agriculture Department will help with other costs. The White House was unresponsive to a Brown request that the three affected counties be made eligible for disaster funds.
Whatever the cost, California must bear it or risk losing billions of dollars in future years. According to the state Department of Food and Agriculture, should the fruit fly become established in the state, the cost would exceed $400 million a year.
A spokesman for the California Control Commission says the infested area will have to be sprayed from the air at least five more times, and 12 sprayings are qu ite possible over the next three to four months.
Plant quarantine officer Mike Mason said the effort to strip fruit from trees in the infestation zone and dispose of it has been largely successful. He is less certain about the effort to keep people from taking fruit out of the quarantine zone. Several major freeways leading to Oakland and San Francisco pass through the area, and if officers stopped every vehicle it would create "an unbelievable traffic jam." So they concentrate on "high risk" vehicles -- trucks , buses, campers, and out-of-state cars. Violators of the ban are subject to stiff fines and jail sentences.
There is wide agreement among those who have worked for years in the field of insect control that a well-run malathion-spraying program, along with other measures, can eradicate the Medfly. Vernon Burton, an entomologist at the University of California, Davis, points out that the fruit fly doesn't wander far from the spot where it is hatched. Thus, the importance of keeping humans from transporting the larvae, in fruit, from one area to another.
According to Mr. Burton, aerial spraying of malathion effectively wiped out Medflies -- with no reports of harm to people -- in a large area of Florida in 1956; again in Florida in 1962 and 1963; in Texas (1966); and the Los Angeles area (1975).
What of the question that "politicized" the current Medfly control effort -- possible harm malathion could do to residents?
At least one limited study aimed at determining long-term effects of the pesticide has been initiated in connection with the spraying program here.
But most experts seem to agree with Arthur Craigmill, a toxologist at the University of California, Davis, who says: "The evidence is pretty solid that there is no need for concern."
Malathion, he adds, has been thoroughly tested over the last 20 years and is considered the "safest organo-phosphate" compound around.
"We don't know everything" about long- term effects, Mr. Craigmill admits. But he adds that researchers put the chance of a person being harmed by malathion at "one in a million -- the same as for being struck by lightning."
Governor Brown's own committee of experts carefully considered the possible effects of malathion on the heavily populated South Bay Area before recommending aerial spraying. They weighed the risks against the benefits and found the risks very low and the benefit to be virtually a necessity.
But Brown, responding to clamor led by local officials, felt he had to try to stop the Medfly without sending out the helicopters. How and why he reversed that decision is a matter that w ill no doubt arise in a later context.