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Insect Paradise. Lovers of wildlife often rhapsodize about the "balance of nature that keeps all living creatures in harmony," but scientists realistically point out that the balance was upset thousands of years ago when man's invention of weapons made him the king of beasts. The balance has never recovered its equilibrium; man is the dominant species on his planet, and as his fields, pastures and cities spread across the land, lesser species are extirpated, pushed into refuge areas, or domesticated.
Some species, most of them insects, benefit increasingly from man's activities. Their attacks on his toothsome crops are as old as recorded history—the Bible often refers to plagues of locusts, canker-worms, lice and flies—but their damage was only sporadically serious when population was small and scattered. Modern, large-scale agriculture offers a paradise for plant-eating insects. Crops are grown year after year in the same or nearby fields, helping insect populations to build up. Many of the worst pests are insect invaders from foreign countries that have left their natural enemies behind and so are as free as man himself from the check of nature's balance.
Agricultural scientists try hard to find ways to check insect pests by tricks of cultivation. They import the ancient enemies of invading foreign insects and foster the resident enemies of native pests. They are developing bacterial diseases to spread pestilence among insect populations. Because these tactics alone are seldom enough to protect the tender plants of modern, high-yield farms, the use of insecticides is economically necessary. Tests run by the Department of Agriculture show that failure to use pesticides would cost a major part of many crops; a 20-year study proved that cotton yields would be cut by 40%. Production of many kinds of fruit and vegetables would be impossible; unsprayed apple trees, for instance, no longer yield fruit that is sound enough to be marketed.*Potato fields swept by the Colorado beetle or late blight (the fungus that caused the great Irish potato famine of 1846) yield hardly any crop.
A Quandary of Surpluses. Chemical insecticides are now a necessary part of modern U.S. agriculture, whose near-miraculous efficiency has turned the ancient tragedy of recurrent famine into the biologically happy problem of what to do with food surpluses. Says Entomologist George C. Decker of the Illinois Agricultural Experiment Station: "If we in North America were to adopt a policy of 'Let nature take its course,' as some individuals thoughtlessly advocate, it is possible that these would-be experts would find disposing of the 200 million surplus human beings even more perplexing than the disposition of America's current corn, cotton and wheat surpluses."
Many scientists sympathize with Miss Carson's love of wildlife, and even with her mystical attachment to the balance of nature. But they fear that her emotional and inaccurate outburst in Silent Spring may do harm by alarming the nontechnical public, while doing no good for the things that she loves.
* In the smaller orchards of prespraying days, fruit had a better chance to escape heavy insect damage, and since quality standards were lower, moderately damaged fruit often went to market.