SELMA, Calif. — Fruit grower Parry Klassen donned protective coveralls and a respirator last month, mixed up a tankful of chemicals and rolled a tractor between the rows of peach and nectarine trees on his 10-acre patch, shooting a worm-killing pesticide into the leafy branches.
He says the chemical, a type known as an organophosphate, is his best, and often only, line of defense against the peach twig borer and the Oriental fruit moth--perennial pests that can drill into the fruit and wreck harvests for thousands of farmers.
But there's a problem: In the pantheon of pesticides, organophosphates, or OPs, are considered the most lethal--to human beings as well as insects.
Come next year, under a sweeping new food safety law, the federal government might very well plow them under.
Because of their potency, OPs--initially used as chemical warfare agents--are the first class of insect killers to face renewed scrutiny under the Food Quality Protection Act of 1996. The law imposes stricter standards that for the first time measure the cumulative effects of similar pest-killing compounds on people. It also puts special emphasis on eliminating exposure to children and infants.
Under the act, all pesticides must be reevaluated over the next decade to determine when and in what doses they may be used. That review will encompass 300 active ingredients and nearly 10,000 uses. By August 1999 alone, officials must reassess 3,000 uses of dozens of organophosphates and carbamates, a similar group of pesticides that is also ubiquitous in farming.
It is likely to mean unprecedented prohibitions against widely used pesticides. For agriculture, the changes promise to be even more significant than the move away from DDT and related insect killers in the late 1960s and 1970s.
At the very least, the shift will accelerate the transition--already underway on the nation's fruit and vegetable farms--to biologically based pest management methods and reduced-risk pesticides.
The environmental community says it will settle for nothing less, citing rising concern that OPs can disrupt the brain development of fetuses and infants.
But the prospect of a ban has spooked Klassen and scores of other growers in California, where OPs are among the most prevalent pest stoppers.
Alternative treatments, if they exist, often cost four times as much and are far less effective, farmers say. For many growers, organophosphates mean the difference between profit and financial hardship.
"For a relatively small farmer that works in the orchard on weekends, I've got enough money wrapped up in this that I can't afford any mistakes," Klassen said.
The loss of these chemicals, growers contend, could decrease crop yields, boost dependence on imports and raise food prices, making it tougher for poor Americans to buy fresh fruits and vegetables. It could also complicate life for homeowners, since many of these same products are used to kill crab grass and cockroaches.
The consequences could be especially acute in California, the leading agricultural state and the primary or sole supplier of several foods, such as lettuce and almonds, whose producers depend on organophosphates. Such "minor," small-acreage crops usually do not warrant the costly research by chemical companies into less toxic alternative pest treatments.
Despite OPs' importance, "they're well worth doing away with," said Robert L. Bugg, an entomologist at UC Davis who helps farmers reduce the use of synthetic chemicals. "We have yet to develop farm families and farm workers that have resistance, and I don't see that on the horizon," he added.
Organophosphates are related to nerve gases such as sarin, which was used in a lethal 1995 attack in the Tokyo subway. Among the least toxic is malathion, sprayed in years past in California to kill Mediterranean fruit flies. At the high-risk end is chlorpyrifos, used to fumigate buildings.
Growers offer a litany of reasons why OPs and carbamates should not be zapped. The chemicals, which kill insects through their nervous systems, treat a wide variety of pests at low cost and break down quickly in the environment. They are used in rotation with other treatments, which helps keep insect pests from developing resistance.
They are often used when crops are dormant, so the chemicals don't come into direct contact with the fruits or vegetables. And, by using OPs, growers say, they can cut down on the total amount of pesticide they must use.
However, such convenience comes at a price for public health. Since 1982 in California, more than 6,600 poisonings--with symptoms ranging from vomiting to blurred vision--have been linked to OPs and carbamates; just under half involved farm workers. The chemicals also have caused 16 deaths since 1982, most involving their use to commit suicide.