Economic Entomology and Insecticides

Stand dismayed, you farmers
wail, you vinedressers,
for the wheat, for the barley;
the harvest of the field has been ruined.

Joel 1:11

Spray, farmers, spray with care,
Spray the apple, peach and pear;
Spray for scab, and spray for blight
Spray, O spray, and do it right.

E.G. Packard

In order to understand the controversy over DDT, one must first see it in context. In 1945 the "atomic bomb of insecticides" was a novelty, but chemical insecticides were well established, to the point that they were almost synonomous with insect control. Farmers, economic entomologists, and government agencies had had a half-century of experience in using, recommending, and regulating insecticides. They had a frame of reference into which they would easily fit the new chemical and others like it. It was this frame of reference, a set of unspoken and almost unconscious assumptions about the need for, and the uses, disadvantages, and possible dangers of chemical insecticides, that accounts for the enthusiastic and almost uncritical acceptance DDT found in 1945, and that helps explain both the wide use and the passionate defense conducted later.

The frame was assembled in the late nineteenth and early twentieth century, as economic entomology and chemical insecticides grew out of efforts to meet the problems of insect infestation that plagued the American farmers in this period. Although these were years of enormous agricultural expansion, they were troubled times. Falling crop prices, high railroad rates, and natural disasters made farming an often frustrating business. Among the difficulties was an increase in insect damage to crops, a problem one historian has labeled the "insect emergency." So it must have seemed to the inhabitants of the Great Plains and, to a lesser extent, to the rest of the country. In the 1870s a series of grasshopper swarms ate up the crops. They were followed by the chinch bugs, which ruined farming in the eastern edge of the Plains. The army worm, the cotton worm, the codling moth (apple worm), Hessian fly, Colorado potato beetle, and a host of other pests devoured the crops. Even in Golden California various scale insects threatened to wipe out the young citrus fruit industry.

The insect emergency was in large part due to the progress of the period: the spread of commercial agriculture across the continent, the regional specialization that was coming to mark production for a national market, and the increased speed and volume of transportation meant that diverse ecosystems were being replaced by simpler ones, by continuous areas of food and shelter for the insects that ate the crops, and that railroads and wagons were busily (if unintentionally) spreading pests to these new and attractive homes. An excellent case in point is the Colorado potato beetle. In the early 1860s wagons returning from the Colorado Rockies brought the beetle from its native habitat, where it lived on a variety of plants, to Illinois. There it found ideal conditions, enormous supplies of food (it quickly came to favor the potato vine), few natural enemies adapted to prey on it, and relatively continuous cultivation. It spread from patch to patch, flying or traveling on wagons.

Native insects that developed a fondness for crops were only part of the farmers' problems. There were other insects that normally preyed on the crops and, in addition, many European pests accidentally introduced into the United States by steamship and clipper. These posed a particularly serious danger. Most American crops were native to Europe or Asia, where their pests had developed along with enemies to prey on them. Settlers had brought the crops and commerce seemed, inadvertently, to be bringing the pests, but there was no one to fetch the parasites and predators. As a result, insects that were not important problems in their homelands caused enormous damage here. The fluted, or cottony-cushion, scale, which threatened the California orchards in the late nineteenth century, was native to Australia. The gypsy moth came from Europe, the boll weevil from Central America (via Mexico). In 1897 the head of the USDA's Division of Entomology, Leland 0. Howard, found that thirty-six of the seventy-two most dangerous insect pests in the country were of foreign origin and another six were suspected of being aliens. Worse, Howard warned, there were others, such as the Mediterranean fruit fly, which might enter at any time. He ended with a plea for an adequate quarantine inspection service.

The transportation of insects around the world and their adaptation to new areas was a significant part of the breakdown of isolated floras and faunas that took place in the nineteenth century. American farmers, though, if one may judge from the literature, cared little about the biological significance of their problems. They just wanted to get rid of the pests, and in their desperation they turned to all kinds of remedies, from patent bug-killing machines and days of prayer and fasting (declared by the governor of Missouri during the "hopper" epidemics of the 1870s) to a bewildering variety of washes, emulsions, baits, and sprays. The favorite remedy, which gained in popularity during this period, was chemical poison. The first chemical used on a large scale was paris green — a common pigment for paints and wallpaper — and its first target was the Colorado potato beetle. Beyond these few facts, it is difficult to trace the early history of insecticide use. There were several claimants to the honor of inventor of the beetle poison. In 1868 a farmer in Fond du Lac, Wisconsin, said that an Iowa man had told him that paris green mixed with ashes and sprinkled on the vines would poison beetles. The same year J. P. Wilson patented a solution of one part paris green to two parts mineral oil for the same purpose. Other stories circulated through the rural press, along with recipes. It is probable that several people independently made the discovery. Paris green was, after all, copper aceto-arsenite, and everyone knew, if he knew nothing else about it, that arsenic was a deadly poison. What more natural than to put it on the vines and see what happened?

The use of chemicals increased, slowly at first, then faster and faster. Farmers tried paris green on other crops, tried other arsenicals, and worked on sprays and spraying equipment. Mixtures of lime, sulfur, and salt became popular for orchard sprays and kerosene emulsions found favor against sucking insects. By the late 1880s the newly established agricultural experiment stations, established under the Hatch Act of 1887, were giving the farmer professional advice, and by the end of the century a small but growing insecticide industry was both supplying materials and sending salesmen into the field to tell the farmer how to use the product. Chemical control was becoming an accepted weapon against almost all insect pests.

The increasing use of insecticides coincided with the rapid development of economic entomology under the auspices of the government. Although the federal government had employed an entomologist, Townend Glover, since 1853, and various states had employed entomologists, there were no groups that could call themselves economic entomologists; nor did the lonely practitioners have much public recognition. Indeed, when swarms of grasshoppers swept over the Great Plains in the 1870s and the westerners demanded relief, Congress completely ignored Glover and the Department of Agriculture. Instead, it appropriated $18,000 for an investigation by the Geological Survey. The Survey promptly chose two of its former agents, Cyrus Thomas and A. S. Packard, who had done entomological work, and filled out the new U. S. Entomological Commission with the state entomologist of Missouri, Charles V. Riley.

The commissioners knew of no remedy for the grasshopper outbreaks, and their only service to the community was to predict the extent and duration of the infestation, a service Riley had done for Missouri. Its most important contribution was to establish Riley in the federal service. Glover retired in 1878, the Entomological Commission was transferred to the USDA, and Riley became head of the Division of Entomology. Except for two years (1879–1881) he headed the division until 1894. Though he was, like Glover, a self-trained naturalist and entomologist, he was a very different sort of administrator. Where Glover had been content to occupy a niche, Riley set out to build an empire. His assistant and successor, Leland O. Howard, described him as a "restless, ambitious man, a great schemer, and striving constantly to build up a large organiztion." Riley's schemes, in fact, helped ease him out of government. His constant lobbying, attempts to build the division, and political connections (by which he sought to preserve his position) eventually led to clashes with the Secretary of Agriculture and to his resignation in 1894. Before he left, though, he laid the foundations on which his former assistant built.

Howard became the chief, a position he retained until his retirement in 1927. He was the real empire builder. Under his leadership the bureau (it attained that status in 1904) became a respected and established part of the government, and he played a large part in making economic entomology a professional applied science — a group with standards, training, entry requirements, and a defined public mission recognized by its practitioners and the public alike. The process was intimately connected with the rise of chemical insecticides and with the establishment of the institutions and bureaus that played a crucial role in the rapid and widespread use of DDT after World War II.

When Howard took office there was little formal training for economic entomologists. They were usually naturalists who had taken a scientific interest in the problem. Riley, for example, had been raised and educated in England and had come to agricultural entomology only when he arrived in the United States and, at the age of seventeen, began work on a farm west of Chicago. Others of his generation came from disparate backgrounds. Cyrus Thomas had been first a lawyer, then a minister. In 1869 he had become an entomologist and botanist in the Geological Survey of the Territories and, for a short time, a professor of natural history. He eventually abandoned entomology for ethnology and took a position with the U. S. Bureau of Ethnology. John Henry Comstock of Cornell, who had been head of the Division of Entomology for two years (1879–1881), C. H. Fernald, credited with first using lead arsenate as an insecticide, Stephen A. Forbes, president of the American Association of Economic Entomologists (AAEE) in 1893 and 1909, and A. J. Cook of Michigan, a pioneer in both arsenicals and kerosene emulsions, were "distinctly self-trained and self-educated in entomology." Howard was professionally trained, but he had been Comstock's first student. By the 1890s, though, the pioneers of the profession had the raw material at hand to form a professional group. The Morrill Act of 1862 had created a system of higher education that the Department of Agriculture could shape to its purposes, and the Hatch Act of 1887 provided agricultural research stations at each college. The personnel of the station were both employees of the Department of Agriculture and faculty members of the University, an interesting if somewhat vexing situation, and the federal government, through an annual appropriation, supported the station and had some control over the research. The Act changed the department from a small agency in Washing ton to a "nexus of semiautonomous research institutions permanently established in every state" and provided the first job market for economic entomologists.

Before he left, Riley had taken the first tentative steps to weld this group together. In the January 1889 issue of Insect Life, a Department of Agriculture periodical, he suggested forming a professional organization of government entomologists. That summer Howard and James Fletcher, the Dominion entomologist (Canada), worked out a constitution, and there was an organization meeting in August at the convention of the American Association for the Advancement of Science in Toronto. Riley was chosen president. The new group, the Association of Official Economic Entomologists, at first limited membership to those who held positions with the government or an agricultural experiment station. It soon dropped the requirement and the word "official" from its title, but it retained ties to the government and drew most of its members from the ranks of official entomologists. Until the society began the journal of Economic Entomology in 1908, the Division of Entomology published its proceedings, first in Insect Life, then in the bulletins of the division. Most of the active members, and almost all who presented papers, were official entomologists, and these men dominated the officers of the association.

When Riley stepped down, though, the division was still groping for a mission. Rather than looking for problems to solve, it let them develop and waited for others to seek its advice. It had a minute budget (about $20,000 a year), a handful of people, and little prestige. The process of change and development that made the Bureau of Entomology a secure and established agency in the next twenty years followed a path others also trod. In Science and the Federal Government, A. Hunter Dupree outlined the general characteristics of the scientific bureau that grew up in the period after the Civil War, features apparent in the new Bureau of Entomology. A scientific agency, Dupree said, was problem centered, not discipline centered. It did not seek to advance a particular scientific discipline on a broad front, it tried to apply the techniques and knowledge of the discipline to a particular set of important, public problems. Each bureau sought to establish itself as the recognized expert on certain problems and to realize some continuity, ideally through a Congressional grant of power, for continuing regulatory or administrative functions.

The ideal bureau chief sought other goals as well: control over the budget, a loyal corps of workers, and a stable set of outside alliances. Some agencies, such as the Public Health Service and the Forest Service, put their employees into uniform; most, though, built morale and loyalty by fostering a sense of common purpose. The ideal bureau chief cultivated strategically placed Congressmen, sought connections with universities, which could provide new recruits for the agency, and with professional groups. And, in all cases, the bureau sought to serve some personal and interested segment of the population that would provide political support.

The Bureau of Entomology fit this pattern quite well. It had a field in which it could, and did, establish itself — the study and control of insects injurious to man, animals, and crops. The division of the bureau into groups organized around particularly important insects of types of crops reflects the emphasis on the application of knowledge rather than the development of entomology. Passage of the Insecticide Act of 1910 and the Quarantine Act of 1912 gave the bureau continuing responsibilities in agriculture as well as more power to carry out its mission of aiding the farmer. Its close association with the American Association of Economic Entomologists is evidence of its concern for outside allies, and the connections between the Department of Agriculture and the land–grant colleges and experiment stations provided a source of personnel, local agents to handle particular problems, and a further source of political aid.

"By 1916," Dupree noted, "the metamorphosis of the Bureau of Entomology into a new scientific agency was virtually complete, and it was proving its worth so regularly that its position in government was not only secure but taken for granted." The bureau had "proved its worth" by suggesting methods of insect control that would solve the farmers' problems, and the way in which it met its responsibilities led directly to the atmosphere in which DDT was uncritically accepted and widely (some would say indiscriminately) used. The bureau and economic entomologists in the experiment stations became committed to chemical control at the expense of other methods and, according to some entomologists, at the expense of the scientific discipline itself.

How did this situation come about? Why did the economic entomologist, whom Stephen A. Forbes described in 1915 as an "ecologist pure and simple, whether he calls himself so or not...." turn so far away from this study that another founder of the discipline could, in 1924, complain that the younger generation of scientists was "losing sight of the insect"? There is no simple answer, for individual entomologists tried and recommended other methods, and the Bureau of Entomology continued work on cultural and biological controls for years. The advantages that chemical insecticides offered for the official economic entomologist, though, played a major role. The economic entomologist "justified his work and made his claim for federal and state funds upon his ability to make sound recommendations for the control of various insect pests," and insecticides, more than their major competitors, provided control that was satisfactory to the farmer, whose demands the bureau had to satisfy.