DDT, Silent Spring, and the Rise of Environmentalism

Classic Texts

Thomas Dunlap

• Publisher: University of Washington Press
• Year: 2015
• Print ISBN: 9780295988344
• eBook ISBN: 9780295998954
• Topic: Ciencias biológicas
• Subtopic: Ciencia medioambiental

No single event played a greater role in the birth of modern environmentalism than the publication of Rachel Carson's Silent Spring and its assault on insecticides. The documents collected by Thomas Dunlap trace shifting attitudes toward DDT and pesticides in general through a variety of sources: excerpts from scientific studies and government reports, advertisements from industry journals, articles from popular magazines, and the famous "Fable for Tomorrow" from Silent Spring. Beginning with attitudes toward nature at the turn of the twentieth century, the book moves through the use and early regulation of pesticides; the introduction and early success of DDT; the discovery of its environmental effects; and the uproar over Silent Spring. It ends with recent debates about DDT as a potential solution to malaria in Africa.

PART 1

BACKGROUND

What people thought about nature and what they had for insecticides shaped their reception of DDT. The first two selections present two views of humans and nature, both well established in Western societies, through speeches by two eminent economic entomologists, made during the years when lead and calcium arsenate were becoming the pesticides of choice and the only alternatives—expensive and very temporary—were plant materials like pyrethrum, an extract from a flower grown mainly in Africa. One argued for control based on fundamental studies of insects and their ecology, including their interactions with humans, while the other, seeing an immediate crisis, argued that we needed chemicals now to win a “war against insects.” Their stands came, at least in part, from their backgrounds. Stephen Forbes began as a medical student and, following service in the Illinois cavalry in the Civil War, became a naturalist and the head of the Illinois Natural History Survey (still in existence and now doing ecological research). Advising Illinois farmers at a time when effective chemical pesticides were not widely available, he became an expert on nonchemical insect controls, a stand perhaps made more emphatic by his own pioneering work in ecology. Leland O. Howard, a generation younger, also began in medicine but went into federal research at a time when materials and methods made chemicals much more effective. “The War against Insects” came from the heart, for he titled his autobiography Fighting the Insects.

The next piece comes from the last major study of lead arsenate, a survey by the U.S. Public Health Service of some 1,200 people living in an apple-growing area in Washington State, done just a few years before DDT replaced it. This work used measures of safety that had guided early studies like the 1928 “Analyses of Sprayed Apples for Lead and Arsenic,” measures based on sickness. That study reported the amounts of residues on apples “that had received the standard spray schedule comprising five applications of lead arsenate (four lbs. to 150 gals.), during the season of 1927.” They found some lead and arsenic, but on the average levels were “considerably below the limit adopted by the [British] Royal Commission on Arsenical Poisoning in 1903 (1.429 mg. per kg.) [milligrams per kilogram] [and] no sample . . . exceeded that limit.”¹ Early and late, this work assumed that materials stayed where they were applied, that the health of people occupationally exposed gave adequate warning of problems in the wider population, and that chronic, low-level exposure produced the same symptoms and problems as large doses.²

The next report comes from the wartime tests on DDT. Done by some of the same scientists involved in the lead arsenate work and designed to measure the effects of short-term exposures, it looked at acute conditions and symptoms under what were expected to be wartime conditions, and the research assumed exposure would end with the war. But as Paul Dunbar, an FDA scientist, admitted to a congressional committee investigating food and drug safety around 1950, wartime tests had been incomplete, and the decision to use DDT was “a calculated military risk” (a selection from one of Dunbar’s speeches is on p. 51).³ Public health workers could accurately estimate how many would die or be made ill if the sprays were not used, and against that toll the risks of unknown long-term damage seemed acceptable, particularly since most people exposed would be people in good health. What they could not calculate and did not know was that DDT behaved in the environment and people’s bodies in a very different way than the arsenates and that animals, fish, and other creatures, as well as humans, would suffer from its use.

1. Albert Hartzell and Frank Wilcoxon, “Analysis of Sprayed Apples for Lead and Arsenic,” Journal of Economic Entomology 21 (February 1928), 125–30.

2. The medical literature shared these views. See “Dangers of Lead Arsenate as Spray in Orchards,” Journal of the American Medical Association 105 (17 August 1935), 531; “Spray Residue on Foods” (editorial), Journal of the American Medical Association 108 (3 April 1937), 1178; “Hazards of Contaminated Fruits and Vegetables” (editorial), Journal of the American Medical Association 109 (10 July 1937), 135.

3. Testimony of Paul Dunbar in U.S. Congress, Chemicals in Food Products, Hearings before the House Select Committee to Investigate the Use of Chemicals in Food Products, 81st Cong., 2nd sess. (Washington: Government Printing Office, 1951), 236.

1

The Ecological Foundations of Applied Entomology

STEPHEN A. FORBES

Applied entomology is peculiarly an American subject, and here if anywhere in the world it should have accomplished its ends or should at least be in sight of its goal; and yet we have to acknowledge that, after generations of work upon them, many of the great long-standing problems of our American entomology are still unsolved, and that the people of our country are still suffering enormous losses of various description because of this fact. It is not because we do not know what we commonly call the entomology of the chinch-bug and the Hessian fly and the white-grubs and the cotton-moth that we are so nearly at our wit’s end in our efforts to devise means for their control; it is because the knowledge of their entomology merely is not sufficient for the purpose. We are obliged to apply for assistance to the physiologist, and the chemist, and the physicist, and the meteorologist, and the geographer, and the agriculturist, and the animal husbandman, and the bacteriologist, and the physician, and the sanitarian, or, in a word, to the ecologist, who, from the nature of his studies, must, if he is thoroughly to cover his field, be something of each and all of these, and still something more.

The last and most essential phase in the expansion and development of our subject is the actual, practical, thoroughgoing application of the products of all our work. . . . Entomology which is not applied is not of its purposed end. . . .

This is an especially important point to us just now, for before we can discuss intelligently the foundations of applied entomology we must know how far the structure is to extend whose foundations we are about to plan. It is my insistent argument that it must, in the very nature of the case, cover the whole field of publication, education, community organization, cooperative effort, and legal compulsion necessary to give the fullest effect to the practical outcome of our entomological work; that our responsibilities, as official entomologists at any rate, do not end until we have done our best to see that all this is done or at least provided for. Just what this signifies with respect to the ecological foundations of applied entomology we shall be in better position to see when we have come to conclusions as to the meaning of ecology itself, and as to the general relations of that subject to entomology as actually applied. . . .

Let us agree, then, that, for the purposes of this discussion at any rate, the subject matter of ecology may be defined as the relation of organisms to their environment, and that this means the whole environment, organic and inorganic, and any and all organisms, man included—man, indeed, as by far the most important living factor, from whatever point of view. And let us also understand that the relations meant are, first, relations of interaction—dynamic relations, of efficient cause, and effect produced upon the organism by its environment and upon the environment by the organism; second, space relations, of distribution, position, juxtaposition, and association—static relations, we may call these, since they show the status of an individual or a group at a given time with reference to the various objects of its environment; and third, successional relations, time relations, sometimes called genetic because, in showing the static relations of a group in successive periods, they trace the genesis of the present status. . . .

Furthermore, there can be no doubt that it is primarily the dynamic factor only in ecology which interests the economic entomologist. It is only what insects do which gives them any importance, and it is only what can be done to them or about them in turn which gives applicable value to our knowledge of them and of their economy. We wish to know where they are or may be, how they are associated, and from whence they have come and by what they are likely to be succeeded, simply because their activities make them important to us. If they were inert we should not care. . . .

And now what shall we say of that view of ecology by which man, with his unrivalled powers of action and influence—the center and source of the most amazing interactions ever known between an animal species and its environment—is left practically outside the natural system, or is looked upon at best as a merely monstrous overgrowth of it—a pathological influence, a destructive enemy of nature, all whose works are artificial as compared with the natural effects and products of the vital activities of ants and caterpillars and crawfishes? There are ecologists to whom primitive nature is the earthly paradise, and civilized man is a kind of fiend, a Satan bent upon its destruction—a triumphant Satan who seems bound to reduce the whole earth, except, perhaps, the national parks, zoological gardens, bird preserves, and the like, to conditions as unnatural, as abnormal, as those of a prison or a hospital. Their ecology is a system not of this present time but of the world before Adam, before the fall of man had introduced into the world the germs of that fatal and frightfully contagious disease known as civilization. . . .

The ecological system of the existing twentieth century has man as its dominant species—dominant not in the sense of the plant ecologist, as simply the most abundant—for which idea prevalent would, I think, be a better term—but dominant in the sense of dynamic ecology, as the most influential, the controlling or dominant member of his associate group.

In applied entomology this is all of course very obvious, and needs no elaboration; for the economic entomologist is an ecologist pure and simple, whether he calls himself so or not—a student primarily of the interactions of insects and men, of that part of the actions and ecology of insects by which the welfare of man is affected, of that part of the ecology of insects which overlaps upon the ecology of man and that part of the ecology of man which overlaps, or can be profitably made to overlap, upon the ecology of insects. And it is the human interest which predominates and controls; the motive to applied entomology is primarily humanitarian. If there were no human interest to which entomology is applicable, there would be no applied entomology.

Now, since the field of applied entomology is precisely and solely that part of ecology in general over which the ecology of man and that of insects is coincident . . . , it must be evident, a priori, that a knowledge of the broad field of ecology as a whole, and of its general aims, principles, processes, and products, is fundamental to the special studies of the economic entomologist. It is only in some such sense as this that we can properly speak of the “ecological foundations of applied entomology” at all. The very substance of applied entomology being ecological through and through, it can have a foundation in ecology only as a part of a whole. . . . It is my special task, therefore, to point out and illustrate some of the ways in which general ecology may be made helpful to applied entomological ecology, and, vice versa, ways in which applied entomology may be made useful—is already useful, indeed—to the student of general ecology. . . .

How many of our measures of protection and defense against insect depredations depend upon any precise knowledge of general fact or scientific principle, or are traceable to anything better than a purely empirical warrant? If we attempt to analyze what we know and what we still need to know concerning any one of the great insect pests before we shall be in a position to do all that can be done and ought to be done to restrain its ravages and injuries either by measures of avoidance, prevention, mitigation, or arrest, we may perhaps get a clearer, concrete idea of what is involved in economic entomology, and what are the foundations of fact and principle upon which it rests. . . .

We know the ordinary life history of the chinch-bug fairly well, although our knowledge is still lacking in the details of variation of life history in different regions, seasons, and climates; while of its so-called physiological life history we know almost nothing exact. . . .

We know that certain insecticide substances in solution or emulsion are effective against it in a way to make them practically available, but we do not know how or by what properties they produce their fatal effects and we are consequently without definite guidance in our search for other such insecticides.

We know that any and all measures against this insect are of comparatively little avail if undertaken sporadically, by an individual only here and there; that for their fair and full effect they must be made the fixed policy and practice of whole communities, actuated by the community motive as well as the personal one. We know indeed that a large part of our applied entomology fails of its application because communities are not brought to the point of cooperative action in the general interest; but we do not know—we have scarcely discussed among ourselves—the best means of appeal and the best methods of organization and management to effect these results, without which much of our economic entomology must fall practically short of the economic end. . . .

If you ask me now whether we should be any nearer the practical control of our most dangerous and destructive insect pests if we had the details of their ecology well worked out, I shall have to answer that I do not know, any more than the entomologists who studied the habits and general ecology of mosquitoes foresaw the use of their observations as an indispensable link in the study and control of malarial disease—any more than Laveran knew when he found a blood parasite associated with malarial disease in man that the remaining links in the chain would presently be traced. . . .

To me it seems so evident that such a knowledge would be of the greatest value to the investigating economic entomologist, that I am quite prepared to [say] that the greatest need of applied entomology at the present time is just this kind of scientific ecology, and that it is among our first and most important duties to acquaint ourselves with this field and to encourage, provide for if possible, and assist as we can, serious, exact, and thoroughgoing work in scientific entomological ecology. . . .

If applied entomology is essentially a mixture of human and insect ecology, then it seems clear that courses in general ecology should form a part of the education of the economic entomologist. Indeed, I have much tangible evidence of the value of this combination in the results shown in my own university department of entomology, whose more capable students all tell me of the unique advantage which they find in ecological courses because of the broader outlook and the new point of view which these give them, and especially because of the greater theoretical interest of their technical studies when related to the foundation principles of ecology. . . .

I believe that students of ecology itself would be equally, although somewhat differently, profited if they were ...

Table of contents

• Cover
• Half title
• Title
• Copyright
• Contents
• Foreword
• Preface and Acknowledgments
• Introduction
• Part 1 Background
• Part 2 Ddt’s Bright Promise and Neglected Problems (1942–1958)
• Part 3 Rising Concern About New Problems
• Part 4 The Storm Over Silent Spring
• Part 5 Ddt and Malaria
• Notes on Further Reading
• Credits
• Index