A New England Town Sprays Its Elm Trees with DDT Charles F. Wurster Society & Culture Hippo Reads is proud to be working with Oxford University Press to highlight unmissable excerpts from recent and upcoming titles. Today’s post is reprinted from DDT Wars: Rescuing Our National Bird Preventing Cancer, and Creating the Environmental Defense Fund by Charles F. Wurster with permission from Oxford University Press, USA, © 2015, Charles F. Wurster. The robin was twitching, tremoring, convulsing uncontrollably, and peeping occasionally. The student handed the bird to me, and in a few minutes it was dead in my hands. It was April 23, 1963, and I was in my laboratory at Dartmouth College in Hanover, New Hampshire, when the student walked in with the bird. A week earlier the elm trees of Hanover had been sprayed with the insecticide DDT to control the spread of Dutch elm disease by elm bark beetles. In the following weeks 151 dead birds filled my freezer, many of them exhibiting before they died the tremors that we later learned were typical of DDT poisoning. Four of us were conducting a small-scale study of the effects, if any, of the DDT spray program in Hanover. We were shocked by what was happening to the local birds, but we would have expected this reaction to DDT if we had read the scientific literature on earlier DDT spray programs on elm trees. We had not. We soon realized that we had rediscovered what other ornithologists had already reported from DDT spray programs in the American Midwest. We also soon learned that DDT was ineffective in preventing the spread of Dutch elm disease and that another procedure, sanitation without insecticides, effectively protected the elms. This DDT spray procedure was all costs and no benefits. Hundreds of towns were killing thousands or millions of birds while not protecting their elms. The whole thing struck me as absurd and tragic. It became a life-changing event for me. I decided that DDT was a chemical that had to be stopped, although I hadn’t the slightest idea where such a conclusion was going to lead. How Did I Get into This? I was 33 years old and had become what in those days was usually called a conservationist. Now such people have been renamed “environmentalists.” I had a dubious beginning as such a person. When I was about seven and living in a northern suburb of Philadelphia, I came across a couple of snakes. I beat them to death with rocks! I guess I had already “learned” that snakes are “bad.” I soon developed an interest in snakes at a summer camp in the mountains of Pennsylvania as a teenager. It was there that I caught and skinned a number of venomous copperheads. Those snakes made out no better than those original two garter snakes, which they must have been. I also collected box turtles and painted turtles, which I kept as pets for years. They made out much better than had the snakes. I released the turtles back into the wild. By the time I was 10 I had learned to play the trumpet, so I became the camp bugler, blowing 22 bugle calls per day to keep the camp on schedule. That gave me two months each summer at a boy’s camp for free in the Pennsylvania mountains, which contributed much to my knowledge of natural history. I also got interested in guns (and firecrackers), and over several years I earned the rank of “Expert Rifleman” from the National Rifle Association. I still have the medals to prove it. When back in Philadelphia, I sometimes wandered around the neighborhood shooting House Sparrows and European Starlings with my BB gun. I told myself they were pest birds, so maybe I was doing some kind of public service. Looking back on it, I guess I was somewhat out of control. In the late 1940s when I was about 17 and in high school at Germantown Friends School in Philadelphia, I met a biology teacher, naturalist, and outstanding ornithologist named Joe Cadbury, who had a huge influence on me and permanently changed my life. He had a tradition of taking a car full of kids to southern Florida for 10 days during spring vacations. I went on several of these excursions. Most of the group was birding while I slopped around in the Everglades to catch a few snakes. I brought the snakes back to Philadelphia in cloth bags and gave them to the Philadelphia Zoo in return for free entrance tickets. At one point I had several large venomous water moccasins in barrels in my cellar at home. I don’t recall what I was going to do with them, but they generally had nasty dispositions and were not especially pet-like. One morning I was shocked to find all of them dead. About 25 years later my father told me he had dropped rat poison into the barrels. Snakes were apparently OK with my parents, but not large and aggressive venomous ones. One snaky episode remains in my memory. We were sleeping on the beach on Sanibel Island, then undeveloped, in southwest Florida. Biting sand flies were driving us crazy and sleep was impossible, so all six of us got into the big old Packard and the other five smoked cigarettes (excluding me—I never smoked) to fill the car with smoke and choke the sand flies. I guess it worked, but suddenly the car seemed filled with snakes and we all jumped out in a panic. I had caught various snakes, including at least one venomous water moccasin, and the cloth snake bags were hanging by their knots from the strap on back of the front seat. A cigarette spark had fallen onto the bag and made a hole large enough for a snake to escape. Nobody had noticed the smoldering bag, since the car was already full of smoke. It was pitch dark, so nobody knew which snake or snakes had gotten out of the bags. It turned out that it was a six-foot-long but harmless chicken snake. I put the chicken snake into a new bag, but my snake-catching activities became less popular with my friends. On the Florida trips I soon realized that in a day the others would see more than 100 species of birds while I caught a few snakes. I seemed to be on the short end of the stick. Birds were vastly more numerous, diverse, and interesting. Birds were where the action was. Without any effort, by osmosis through much time with those birders, I had already learned about 200 bird species. That did it. I became a birder for life. In the following 60 years I have seen about 4,000 avian species on all continents, and the DDT issue brought birds into my professional life as well. Maybe I can claim the title “ornithologist.” It was in Florida that I became familiar with the Bald Eagle, our national symbol, a majestic species if ever there was one. Adults are unmistakable with their white head and tail. It was 1947 and they were fairly common in Florida then. I did not know at the time that they would suffer a large decline in numbers in the next two decades, that they would become very scarce nationwide, and that it would be 1970 before scientists had figured out the cause of the decline. The story of that iconic keystone species at the top of its food web will develop as we move along in our chronology of events. By 1950 I had also become familiar with other bird species that I had no idea were beginning to decline. Ospreys were common in Florida and along the East Coast, their large nests on poles and bare trees for anyone to see. We often saw them carrying fish to feed their young. Incredibly, when they catch a fish they reorient it in their talons so that it is carried head first, thus reducing air resistance as they fly back to their nest. Brown Pelicans were abundant in Florida, often playing follow-the-leader in lines over the surf, clownishly entertaining people along the beach. Peregrine Falcons were not common but were occasionally seen in a wild chase through the sky after a panicked shorebird. It would be another decade before anyone knew that something was the matter with these and many other species of birds. I retain a passing interest, indeed somewhat of an appreciation, for snakes. During one lunch hour in the hills above Stanford University, where I was attending graduate school about 1956, I came across a two-foot Pacific rattlesnake. I brought him back to my apartment in my brown paper lunch bag, and he lived in a large bell jar for a year, consuming one white mouse per week. Named “Pretty Boy,” he was gentle, easily handled, and ceased to rattle because he was no longer frightened. He was allowed short outings on the living room floor. This performance spooked an insurance salesman one afternoon, who quickly departed without selling any insurance. Proving that I was a true conservationist by this time, I then took Pretty Boy back to where I had found him, and he was pleased to be free again. I had developed considerable admiration for rattlesnakes by appreciating the extremely complex and sophisticated chemistry of their venom systems, and the brilliant stereochemoreception of their forked tongues for following and consuming rodents. When they inject venom into their prey they also take an imprint of its odors and chemistry, and their forked tongue tells them whether to turn right or left in following it to its demise. It’s too bad that people persecute them, killing rattlesnakes on sight or rounding them up by the hundreds and thousands to be slaughtered in weekend social events. Admittedly, rattlesnakes are not good backyard playmates for small children, but decreasing the rattlesnake population merely leads to more rats. After high school and my somewhat dubious beginning as an environmentalist, my pathway became a bit more conventional. I attended Haverford College and the University of Delaware, I married Doris Hadley, and we both went to Stanford University to complete doctorates, hers in biology and mine in organic chemistry, in 1957. I had a Fulbright Fellowship in Innsbruck, Austria, for a year, and we then spent eight months wandering by land across the Middle East to India, Kashmir, Nepal, and Southeast Asia, then to Japan and ultimately San Francisco. In 1959 I took a job with Monsanto Research Corporation north of Boston, where my research involved jet fuels and laminating resins. But my interests were biological, not product development, so I accepted a postdoctoral research position at Dartmouth College studying lipid biochemistry. It was late in 1962 by then, and that’s where and when the DDT issue surfaced as a major distraction and ultimately as a second, unpaid career that carried on for a decade. Its residue in my life remains today. So what is DDT? It stands for the shortened name dichlorodiphenyltrichloroethane; the full correct name is 1,1,1-trichloro-2,2-bis(p-chlorophenyl) ethane. You don’t need to remember that. As the first in a new family of pesticides, DDT had spectacular success during World War II by blocking transmission of several important insect-borne diseases, especially typhus and malaria (Dunlap, 1981). Insects had no prior genetic experience with this chemical, and they were highly susceptible to its toxic action. Man’s battles against insect pests would be over, it was thought. DDT was the miracle insecticide. As the war ended in 1945, demand was great, virtually unstoppable, for the use of this material to combat every imaginable insect pest problem. By 1946 the use of DDT was worldwide, and great quantities were being released into the environment. During the war, DDT had been rushed into service without anything resembling adequate testing for side effects to nontarget organisms. That is entirely understandable, with many earlier wars having been decided not only on the battlefield but also by diseases. DDT proved toxic to insects, its acute toxicity to humans was low, and there was a war to be won. Few voices were raised concerning potential problems for nonhuman organisms. It was not long after the war before unanticipated problems appeared. Bird mortality and failures at insect control appeared within a few years; the 1950s saw an avalanche of papers describing an assortment of problems with birds, fish, mammals, human health, and ecological disruptions; and Rachel Carson’s Silent Spring was published in 1962. By 1970 there were many hundreds of scientific papers representing an immense amount of research demonstrating that DDT contamination had become a serious worldwide problem. Coincident with damage to nontarget organisms and ecosystems was an increasing failure of DDT to perform its intended function of insect pest control. Resistant pest insect populations developed; natural enemies of pests were decimated, leading to population explosions of the pests; and new insect species were elevated to pest status where they were not before. The nightmarish pest problems created in the Canete Valley of Peru by DDT in the early 1950s serve as a classic story, a forerunner of things to come elsewhere, told later in this book. DDT was doing widespread environmental damage while failing to do its job. DDT Kills Birds But Doesn’t Save the Trees It was at a party in Hanover, New Hampshire, during December 1962 that Betty Sherrard, a local conservationist and birder, circulated a petition calling for the town not to treat its elm trees with DDT in an attempt to control Dutch elm disease. She described fluttering and dying birds near her property and explained that DDT had killed many birds in earlier years. She was circulating the petition because she did not want to see the bird deaths repeated. I signed it, as did others. When the petition was presented to town officials, they said they had applied DDT carefully according to directions on the label, and that the bird mortality in earlier years had been caused by a nerve disease within the bird population, not by DDT. The petition went nowhere in convincing them to alter their intended DDT spraying program. The response of the town officials was typical. In the early sixties, conservationists were politically weak sisters who were largely ignored. The American elm tree had become the most popular shade tree since Revolutionary times, and by the mid-20th century its spreading branches lined the streets of countless American towns and villages. Then about 1930 a new disease arrived from Europe, a fungus disease that clogged the vascular system of the elm trees, choking their water- and nutrient-carrying capacity and eventually killing the tree. The disease was described by a Dutch scientist, so it became known as Dutch elm disease, and it can be transmitted from an infected elm to a nearby healthy tree by elm bark beetles that carry the spores of the fungus. Elm trees are majestic and popular, so they were planted side by side in towns, fostering transmission of the disease. When the miracle insecticide DDT came along shortly after World War II, it was employed by thousands of towns in a single spring spraying to kill the bark beetles as they emerge and before they can spread the disease. Who could blame town officials for their efforts to save their beloved elm trees? Since the elm spray program was to go forward in Hanover in the spring of 1963, four of us, all scientists (except Weber) and birders, decided to conduct a study to see what would happen. Included was my first wife Doris H. Wurster, a pathologist; Walter N. Strickland, a postdoc in biology; and Hans W. Weber, a professor of German. We conducted bird censuses, recording and counting all birds seen or heard before work in the morning and again at lunchtime. We chose study sites in Hanover, to be sprayed with DDT, and compared them with ecologically similar study sites in Norwich, Vermont, a mile west of Hanover across the Connecticut River, which was not sprayed. The elm trees in Hanover were sprayed with DDT during the nights of April 15–18, 1963. The treatment was done at night when wind would be minimal. The following days we expected to find many dead birds around Hanover. Not so! None! That demonstrates how little we knew about studies, published years earlier, documenting that bird mortality could take days to weeks to become apparent (Hickey & Hunt, 1960; Wallace, 1962). The DDT had to work its way through food chains to the birds. We were not yet familiar with the literature, nor had we read Rachel Carson’s Silent Spring. Carson had little influence on our study, nor did any of us ever meet her before her death in 1964. We were unbiased and empty-headed about DDT as our study began. Residents in both towns were alerted by radio and newspapers to bring us any dead or dying birds they encountered. Soon people were bringing us sick and dying birds. Within several weeks 151 dead birds, especially American Robins, had been brought to my laboratory and kept in the freezer; 10 dead birds came from Norwich. Lots of the birds came from the Dartmouth College campus and were brought in by students. They had read about our study in the Dartmouth newspaper and they wanted to help. Many of the birds from Hanover exhibited tremors and convulsions before death, the typical symptoms of DDT poisoning. DDT destabilizes nerves, causing them to fire spontaneously without control, so muscles twitch uncontrollably. We dissected the birds and they were analyzed for DDT content in a laboratory in Wisconsin. Working up the DDT analyses for the several organs of the birds presented a challenge. I was told I needed to calculate geometric means (averages), but I had no idea how to do that. I had majored in chemistry. It was beyond my slide rule, and mechanical calculators at that time were the size of large typewriters, with many spinning wheels and clanking parts. I was told that Dartmouth College had a computer (the first time I had heard the word), and sure enough, it was in the basement of one of the buildings. The computer had a room of its own and was the size of an SUV, and there was a person there who knew how to run the thing. The “program” was a deck of cards with millions of holes. I punched the data as more holes into another deck of cards, and both decks of cards were fed into this monster. Out came a vast printout of paper that stretched across the room, and nirvana, there were the geometric means. They were published in our paper in Ecology (Wurster DH et al., 1965). I didn’t touch another computer for 30 years. Upon analysis, we discovered that all of the birds exhibiting tremors prior to death on analysis contained lethal concentrations of DDT in their brains (Wurster CF et al., 11934880965; Wurster DH et al., 1965). No such birds appeared from Norwich; the few dead birds from Norwich had died of other causes. By this time we had done our homework and caught up with the literature; our findings were quite similar to earlier reports from the Midwest (Wallace, 1959, 1962). It was all right there in Silent Spring, the book some continue to call “controversial” up to this day. The book was a well-written and accurate review of the literature. Have the critics read it? The birds had accumulated the DDT by eating contaminated food: ground feeders from soil organisms, and bark and treetop feeders from contaminated insects in the trees. It was especially noteworthy that Myrtle Warblers, treetop feeders that were hundreds of miles to the south when trees were sprayed, were tremoring or dead in Hanover on the same day that they first appeared on our censuses. Food chain contamination had worked quickly and efficiently to kill the birds. We estimated that about 70% of the robins in Hanover had been killed by the DDT spraying. Birds in Norwich were unaffected. We soon realized that we had rediscovered the stories that earlier authors had already described. Those papers had been published mainly in conservation-oriented magazines, where public impact might be limited. We believed the death of the songbirds in Hanover would be a concern to a wider audience. Accordingly, we published our study in the peer-reviewed scientific journals Science (Wurster CF et al., 1965) and more fully in Ecology (Wurster DH et al., 1965). Scientific credibility was important, since a policy change was among our objectives. When confronted with the results of this study, Hanover officials agreed not to use DDT anymore. In 1964 they substituted the far less destructive insecticide methoxychlor, but because DDT remains in the soil long after its use, organisms living in soil contaminated by DDT still killed some birds who fed on them. By this time we had also learned that DDT is not very effective (nor is methoxychlor) in controlling the bark beetle that spreads Dutch elm disease. The beetle breeds and overwinters in dying or recently dead elm branches, then emerges in spring and flies to nearby healthy elm wood to feed, thereby spreading the disease. By spraying DDT onto the trees while they are still dormant, the intent is to kill the beetles as they arrive to feed in the spring, thus slowing the spread of the disease. More effective in saving the trees is the practice of “sanitation,” the removal and destruction of all breeding material for the beetles—that is, getting rid of dying or recently dead elm branches and even nearby woodpiles. Sanitation substantially reduces bark beetle numbers in the neighborhood, and beetles do not arrive from faraway elms. Unlike elms in the forests, elms in towns were close together and had lined the streets in rows, making the trees susceptible to the epidemic of Dutch elm disease. This nonchemical sanitation of the elms effectively controls spread of the disease, a technique known and published since the 1930s (Wurster DH et al., 1965). We had spent two years stopping DDT in one town, while hundreds of other towns continued to use it, a not especially spectacular performance. Stopping all towns from using DDT on elm trees seemed like a worthy objective. That objective resurfaced three years later in Michigan and Wisconsin, but by that time we had a still more ambitious goal. In September 1965 I moved to Long Island to become Assistant Professor of Biological Sciences at the State University of New York at Stony Brook. Doris and I divorced and she remained in the Dartmouth Medical School. It wasn’t long before the DDT issue bubbled back to the surface for me, this time in a rather different capacity. I had met new friends and allies, and the battle against DDT was soon to be escalated.