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Although the apple growers refused to abandon pesticides, many American farmers in the late 19th century still did not use them, either because they didn't think they needed them or because they feared being poisoned. The number of holdouts was significant enough to rattle the Agriculture Department, which went as far as to put pressure on farmers who didn't apply arsenic, lead or other poisons to their fields. At the department's urging, several states passed laws requiring that all farmers use insecticides, on the theory that the insects in unsprayed fields were bound to infest neighboring farms.

After the turn of the century, medical evidence mounted that pesticide residues on fruits and vegetables were poisoning and in some cases killing people. Emotional pleas for reducing pesticide use were made in books, magazines and newspapers. More than 50 years ago, a book titled ''40,000,000 Guinea Pig Children'' made an appeal strikingly similar to Meryl Streep's: the author warned that children were especially vulnerable to pesticide poisoning because they ate more fresh fruit than adults. As a result of such evidence, the Federal Government in 1947 passed the first law explicitly regulating the use of pesticides.

The law went into effect just as DDT was gaining in popularity. Once farmers had DDT, which worked faster and killed more insects than any chemical they'd ever used, they rapidly abandoned arsenic and other age-old pesticides. Confident that they had the ability to conquer their chief enemies, many farmers expanded their operations. Small farms with a patch of lettuce here and some tomatoes there turned into large farms with a thousand acres of nothing but lettuce. Farming became a factory-style business. And soon after DDT came on the market, other powerful pesticides emerged.

But now enter Rachel Carson. Her book ''Silent Spring,'' published in 1963, described as never before the threat of pesticides, conjuring up a ghostly American landscape: birds were absent, cows had stillborn calves and people lay dying of cancer, all because of pesticides in the air, water and food. Carson, a biologist, supported her case with scientific evidence that DDT and other pesticides persist in the environment for decades, entering the food chain and building up in the tissues of humans and other animals; she also pointed out that babies swallow pesticides with their mothers' milk.

After the publication of ''Silent Spring,'' a consensus grew among scientists and Government officials that pesticides as they were being used had the potential to harm human health. Federal regulations governing the testing and use of agricultural chemicals were strengthened, and in 1972, DDT was banned. (It is slow to break down, however, and is still one of the most commonly found residues in many foods grown in this country.) Despite the increasing awareness of the dangers of pesticides, the amount of chemicals deposited on American farms continued to grow.

The use of agricultural pesticides in the United States peaked in 1982, when 880 million pounds were sprayed, a tenfold increase in the nearly 40 years since synthetic pesticides were introduced. During the same period, farm productivity more than doubled. Clearly, large-scale commercial farming could not exist without any pesticides. But since 1982, their use has been declining, as more and more farmers have come to realize that many of the chemicals they once routinely applied to their fields are not really necessary.

THE DECLINE IN PESTICIDE use is welcome news to people concerned about their health, but many experts take the position that as long as most farmers ignore effective alternatives to insecticides, herbicides and fungicides, these chemicals are being overused. A report released last month by the National Academy of Sciences concludes that alternatives to pesticides not only work but are economically viable. The report indicates that the potential exists for an even greater transformation of American farming than the one now under way. ''You don't need any of the worst chemicals,'' says Charles Benbrook, whose staff helped put together the report. He says that even if a significant number of pesticides were suddenly taken off the market, ''there's no way that any major fruits and vegetables would become unavailable.''

The alternative farming methods cited by the academy include the widespread use of disease-resistant crop varieties, the introduction of beneficial insects and crop rotation - planting a crop in a different field each season to prevent insects, fungi and microbes from gaining a foothold in any one area. In places where these methods would not work for particular crops, the report recommends that they simply not be raised. ''Most fruits and vegetables probably would not be able to be grown in the Southeast, because in hot, humid climates, pests are too great a problem,'' says Benbrook. ''Even now, the cost of pesticides is killing farmers there.'' He believes that virtually all of the nation's fruits and vegetables - the crops that are most vulnerable to insects and diseases - should be grown in California and other hot, dry Southwestern states, where the alternatives to pesticides work best.