The Rise and Demise of the Wonder Insecticide

To the majority of pest control operators today, DDT is an abbreviation for the name of a chemical insecticide out of the distant past a dim relic used by old-timers before it lost its potency and its use became prohibited. But when it was introduced to the public half a century ago, DDT shook the world as a celebrated lifesaver and a decorated war hero that made headlines and captured the public's fascination as no other insecticide ever had or ever would.

DDT's full introduction in 1946 also brought about a detectable anxiety that seemed to permeate the pest control industry. When pest controllers got together, one noticed puzzled, worried looks. Was the newly introduced wonder pesticide, widely touted as a panacea and popularly known by the catchy abbreviation DDT, going to destroy their business? How would this widely heralded, readily available pesticidal upstart fit in with technicians' using time-honored, one-shot inorganic and botanical materials and dangerous fumigants?

DDT was without question one of the technological marvels produced by science during the second World War. Along with the atom bomb, penicillin, the development of blood plasma, atabrine as a substitute for quinine, radar, proximity fuses for mines, and the jet engine, DDT played an important role in the Allies' victory.

DDT also garnered the Nobel Prize in Medicine for its discoverer, Paul Müller, in 1946. Although it was released by the military for civilian use in 1945, DDT's full impact on the pest control industry and the general public wasn't realized until 1946. No insecticide before or since has been invested with more history, drama, promise, and eventual disappointment.

DAYS OF INFAMY. In December 1941, the United States was confronted with war on two fronts. Immediately after the Japanese sneak attack on Pearl Harbor, Nazi Germany, which by then had conquered most of western Europe, declared war on the United States. In addition to a shortage of troops and material, the U.S. faced an acute medical problem: how to protect personnel against insect-borne diseases. Troops fighting in congested areas of Europe would be exposed to typhus, a potent killer. The military in the sweltering jungles in the South Pacific would need protection against malaria and other tropical diseases carried by mosquitoes.

Aside from the potential disease hazards involving U.S. troops, there was concern about the civilian populations that would inevitably be displaced as a result of the war. The available insecticides for countering insect-borne diseases, mostly botanicals, were in short supply. The primary pre-war source of pyrethrum was Japan. Other materials either were grown in inaccessible areas or required shipping, which was scarce because most of the available shipping was being devoted to the war effort, and the civilian shipping that was available would often have had to be routed through enemy-controlled waters.

A STAR IS BORN. Scientists frantically sought a solution to these vexing problems. Then, one day in mid-1942, an American representative of the Swiss firm J.R. Geigy came knocking on the door of the U.S. Department of Agriculture with a compound taken from the company's headquarters in Basel, Switzerland. The compound was a sharp-smelling powder known as "Gesarol." H.L. Haller of the Division of Insecticide Investigations, a department of the U.S. Bureau of Entomology and Plant Quarantine, rushed to analyze the compound.

Haller eventually worked out a synthesis and had the Bureau and the War Food Administration test the new material for insecticidal efficiency. The active ingredient found by Haller was 1,1,1 trichloro 2,2 bis (parachlorophenyl) ethane, also known as dichloro diphenyl trichloroethane, which was eventually shortened to DDT. Along with other chlorinated hydrocarbon insecticides that would follow in its wake, DDT, when applied to laboratory insects, was found to be a slow-acting product with both stomach and contact action offering exceptional residual properties.

The origin of DDT actually dates back to 1874. Othmar Zeidler, a German chemist, had synthesized the compound through the reaction of chlorobenzene in the presence of sulfuric acid. Zeidler was searching for substitution products of aromatic compounds, but nothing of consequence was developed, and the data that was collected lay forgotten for more than half a century.

It wasn't until the 1930s--some 60 years after Zeidler's dead-end research--that practical use for the chemical compound was discovered. Paul Müller, a young chemist working for J.R. Geigy in search of a mothproofer, played around with Zeidler's formula and came upon a compound that proved effective in the laboratory against the potato beetle and the clothing moth.

It is one thing to come upon a chemical that shows insect-killing potential in the lab. But as anyone involved with an insecticide intended for field use knows, it is another matter to know how such a chemical will react on man. After J.R. Geigy's representative called on the USDA in 1942, U.S. government agencies and representatives of the military went feverishly to work conducting safety tests involving human volunteers. The results were encouraging; DDT's acute toxicity was apparently very low.

The first field tests with DDT before its release to the public were conducted by the military at posts around the country. Dr. John Osmun, who would later direct Purdue University's entomology department and make many important contributions to the pest control industry, was then Captain John Osmun, an entomology officer stationed at Camp Gordon, Georgia. Osmun recently recalled some of the work with Gesarol, the J.R. Geigy name originally given to DDT.

"The results on bedbugs and lice were phenomenal," he said. "I remember one day, the first time we treated mess halls and kitchens on the post for thousands of houseflies after closing. The next day we came back and you absolutely couldn't find a live fly."

GEARING UP. By the middle of 1943 testing was completed and DDT became standard military issue. This was followed immediately by a massive outpouring of money and herculean efforts by scientists and engineers aimed at providing a full range of equipment for producing and using DDT. The USDA's Bureau of Entomology and Plant Quarantine developed spray equipment ranging from hand-held aerosol containers, popularly called "bombs," to power sprayers and large tanks and nozzles adaptable for aerial spraying. The government assigned contracts to produce DDT to several companies and pulled out all the stops to expand DDT production. By the end of 1944, Americans had produced 2 million pounds of DDT for military use.

The DDT bomb issued to the military was a pint-sized throwaway container made of lightweight steel from which an aerosol or mist was discharged through a valve. The propellant was freon, a cold gaseous material. In addition to serving as protection against marauding insects, enterprising soldiers took advantage of the freon in the bombs to cool the beer they were periodically issued.

Before the government approved DDT for use, the manufacturers of the first aerosol containers tapped into the rapidly depleting stocks of pyrethrum still on hand. These were directed mainly at malaria-carrying mosquitoes. Once DDT was employed, however, the military had a material that would also prove effective against disease-carrying fleas and lice.

Aerosol bomb manufacturers worked around the clock seven days a week to rush DDT to the war zones. Once Westinghouse Electric, one of the principal manufacturers, was in full production, it cranked out more than 1.3 million units per month. The first formula contained 3% DDT, 2% pyrethrum and 85% freon in an inert oil.

The U.S. Army and Navy equipped aircraft with specialized spraying equipment, and it became common for these planes to sweep over tropical enemy-held areas in conjunction with military offensives. The planes would blanket the terrain with DDT in areas where occupying enemy units were wracked with malaria. Once U.S. forces secured a sprayed area, the terrain was generally insect-free.

MIRACLE IN NAPLES. In late 1943, DDT gained its reputation as a miracle insecticide when, for the first time, it was used successfully to quell a public health crisis in a highly publicized incident involving a civilian population. Allied forces had se cured a foothold in Italy after months of fighting. In capturing the city of Naples from the Nazis toward the end of the year, U.S. and British forces stumbled upon an epidemic of typhus. In July 1943, isolated cases of typhus had been reported in the densely populated Italian port city, but with the coming of winter and the confinement of the population indoors, the louse-borne disease escalated into an epidemic.

Using DDT as a dust and applying the material in a newly developed powder applicator, Allied authorities pumped the insecticide into the subjects' sleeves, waistband, collar, pant cuffs, hair, and hat. This replaced a cumbersome system that involved baking the subjects' clothes, shaving their heads and body parts, and painting the shaved areas with older nit-killing pesticides. A case-reporting system was set up in which public health officers located and dusted the families, fellow workers and neighbors of each victim, killing the lice and breaking the chain of infection. By February 1944 the epidemic had been halted; Allied medics had administered more than 3 million individual dustings to civilians and occupying troops.

News media in all parts of the world reported the dramatic success of DDT in forestalling what promised to be a raging epidemic. It was the first epidemic of the deadly typhus disease that had ever been eliminated through public health measures employing an insecticide. There was speculation that DDT would revolutionize public health. The surgeon general of the Army, Major General Norman J. Kirk, predicted that DDT might bring an end to insect-borne diseases.

GEE WHIZ. The praises of DDT grew far and wide as the war came to a close in 1945. Toward the end of the year, DDT, the first of a promising new group of chlorinated hydrocarbon insecticides, was released for civilian use. There was a barrage of rosy predictions, declarations proclaiming the beginning of a new era of freedom from insects, and wide-ranging hyperbole. As a food company official commented, "The publicity given DDT might well be envied by any Hollywood movie star."

An article by Arthur Bartlett in the May 1945 issue of Popular Science typifies the gee-whiz tone of the superlatives that attended the introduction of DDT. Under the headline "Chemical Marvels Take Bugs Out of Living," Bartlett wrote:

"Picture an American home a few years after the war. Flies, mosquitoes, moths and other insects die as fast as they sneak in. Even microbes are licked before they have a chance to do their dirty work. And Rover, the faithful family dog, shares the blessings of the day to come; fleas and ticks no longer make his life one long session of scratching.

"Using an ordinary spray gun, [the homemaker] sprays her walls with a solution of DDT. As the solvent evaporates, a practically invisible residue remains on the walls, and for months thereafter every fly and mosquito that lights on the walls will die."

At the American Association of Economic Entomologists meeting in New York in 1945 the following statement was adopted by the 392 delegates present, representing the association's membership of 1,600:

"We feel that never in the history of entomology has a chemical been discovered that offers such promise to man for the relief of insect problems as DDT."

There were a few in the science community who, while not entirely skeptical, raised questions about DDT. One of the first to sound a cautionary note was Dr. C.H. Curran, the Associate Curator of Insects and Spiders at the American Museum of Natural History. Curran proclaimed that DDT, the wonder insecticide, might be a blessing but also could be a curse.

"Properly used, [DDT] can eliminate many insect-borne diseases," Curran wrote. "But broadcast over field and forest, it may harm our fish and wildlife, kill the helpful insects essential to agriculture, and even damage crops themselves."

Rupert Wenzel, curator of insects at the Field Museum in Chicago, echoed Curran's sentiments: "Eliminating predator insects in nature with such a broad-spectrum chemical might prove counterproductive in the long run."

Nonetheless, the enthusiasm following DDT's war record and its declared potential as a public health prophylactic drowned out the cautionary warnings of the few museum and research scientists who voiced doubts. On a more practical note, everyone observing applications was astounded at the residual properties of the compound. It was not uncommon for flying insects to drop from invisibly sprayed surfaces months after DDT had been applied. For their part, PCOs were for the first time able to space their regular maintenance calls over longer intervals without fear of intermediate callbacks.

Coinciding with the release of DDT to the public was a serious epidemic of polio in the United States. Years before the discovery of a preventive vaccine, the medical profession was desperate for a solution. Serious consideration was given to flies as possible carriers of the disease, and on August 19, 1945, an experiment was conducted in Rockford, Ill., a city that had experienced 147 cases of polio with 17 deaths since July 1 of that year. Dr. John Paul, a polio authority from Yale University, set up a campaign that divided the city into two areas, one of which was sprayed with DDT from Army bomber jets. In this case, the spraying was completely ineffective; polio was a viral disease and there was never hard evidence to incriminate flies as carriers.

While DDT was unsuccessful in stemming polio, it should be noted that until insecticide resistance became a factor, the compound won universal praise for virtually wiping out malaria, which had been the world's most lethal insect-borne disease.

As the 1940s came to an end, pest control operators faced a situation in which a highly effective new pesticide flooded the consumer market, bringing industry concerns and demands by customers to include DDT in all their applications. Industry consultant Harry Katz vividly remembers when Bill Buettner, one of the founding fathers of the National Pest Control Association and its first executive secretary, gloomily advised PCOs to look into other businesses because DDT had become available over the counter and would eliminate the need for their professional services.

As a retailer of older mothproofing chemicals, Katz also recalls that customers would come in de manding that anything sold contain the new wonder chemical. He said this necessitated his adding DDT to every bottle of material he sold.

The fact that DDT was well adapted to aerial spray programs made it a chemical of choice for large-scale agricultural and open-area mosquito control. Under ideal conditions, as little as one-fourth to one-fifth of a pound per acre controlled adult mosquitoes. At the normal dosage of one pound of DDT per gallon of solution, one aircraft could easily treat wide areas. Additionally, DDT could easily be transported in concentrated solutions and diluted with readily available kerosene or fuel oil. Its solubility prevented the clogged pipes and nozzles that were so common with suspensions and eliminated equipment that was needed to broadcast insoluble materials.

At the time of the release of DDT to the public, an immediate symbiotic relationship was formed between the chemical and a newly introduced fog machine manufactured by the Todd Shipbuilding Company. Todd had been awarded a contract to build smoke screen generators for combat use during the war. The principal of operation was the dispersion of fuel oil that had been heated by a heating chamber to form a blanketing fog of small micron size that concealed ships and invading troops from enemy view. The civilian unit, known as the Todd Insecticidal Fog Applicator (TIFA), lent itself to the inclusion of soluble DDT for mosquito and fly control. In a short period of time many municipalities, mosquito abatement districts, and private fog operators bought TIFAs, which became a common sight throughout the country. These units, usually mounted on trucks or jeeps, drove about "DDTing" mosquito breeding areas and outdoor recreational sites and residential areas.

By 1946 the pest control industry rolled up its sleeves and came around to include DDT in its pesticide arsenal. While the results against German cockroaches disappointed and the effect on termites was questionable, applications against bedbugs, ticks, ants, fleas, silverfish, flies and mosquitoes were uniformly excellent. A grateful public was impressed by the results obtained by the PCOs using the new chemical, a response that helped burnish the image of an industry that needed all the good public relations it could get.

Jim McDaniel of International Exterminators, Elk Grove Village, Ill., remembers using the new material applied both by compressed air sprayer and by means of the company's TIFA fogger immediately after it became available. "We used to have to do rooming houses and hotels for bedbugs at two-week intervals using Oil of Merbane and Lethone, and all we could do was hold them down. Then came DDT, and bingo, we thanked God for sending us the stuff. Every job was a success — we completely knocked them out in one shot," McDaniel said. The veteran Illinois PCO also described successes against flies, mosquitoes and ticks.

Dan Stout, who would eventually be come senior vice president for technical development with Whitmire Research Laboratories (now Whitmire Micro-Gen), was a student when DDT became the cure-all insecticide. He vividly remembers witnessing representatives from the state of Arkansas spraying down sharecropper cottages for flies, fleas and bedbugs, and being amazed at the spectacular results.

In his pest control history The Ratcatcher's Child, Dr. Robert Snetsinger points to a subsequent pest control use for DDT: as a rodenticide. According to Snetsinger, it was Jack Rudick of Western Exterminating Company in Montreal who first discovered that micronized DDT could be used to control mice. Because mice regularly preen and lick their feet and fur, they would ingest the material that eventually killed them as a stomach poison. The dust was widely used in the industry, and invariably brought good results.

THE COUSINS MOVE IN. DDT's use by the structural pest control industry was relatively short-lived; its shortcomings against cockroaches and termites were recognized early on. In rapid succession, several chemical "cousins" were developed and introduced: the more adaptable chlordane, methoxychlor, lindane, toxaphene, aldrin, dieldrin, heptachlor and mirex.

A discouraging report in the January 24, 1946 issue of Science Newsletter reported the first resistance of houseflies to DDT. The article reported that researchers at the U.S. Bureau of Entomology and Plant Quarantine laboratory in Orlando, Fla., had bred houseflies in the 35th generation that had shown evidence of DDT resistance in their third generation. The report further noted that 35 generations of flies in the laboratory would require four years to develop in nature, and offered this understated prediction: "If wild fly strains develop as much or even more DDT resis tance than laboratory insects, future fly control may be more complicated."

During the 1950s, one insect after another developed resistance to DDT. Crop insects were becoming immune and PCOs throughout the country who reported their problems with the compound were advised to alter their formulations. Within a few years a list of more than 100 insects made the growing DDT-resistance list while researchers sought newer products.

As if this wasn't enough to sully the reputation of what was thought to be a wonder insecticide, there appeared on the horizon a growing group of "environmentalists" who ran the gamut from rational scientists to hysterical crackpots. Unfortunately, the hue and cry emanating from this noisy group was directed in one fell swoop against all the chlorinated hydrocarbon insecticides.

The initial antipesticide crowd proved to be an amorphous, largely disorganized group in search of a platform, and largely made its presence known by protesting at community meetings and writing emotional letters to the editor. Then, in 1962, it found a solidifying voice. That voice was a book, Rachel Carson's Silent Spring.

Two years before Silent Spring's publication, William Longgood wrote The Poisons In Your Food, the first major journalistic attack against pesticides. But this was an insignificant, poorly written effort that gathered dust after a meager first printing. Silent Spring was another story. A biologist with the U.S. Fish and Wildlife Service, Carson was also an accomplished, award-winning author who had written several well-received books previously.

Silent Spring sounded an ominous note. Its introductory pages envisioned a bleak spring landscape ravaged by a "strange blight" that caused domestic animals, birds, fish, flowers and trees to die or disappear. "What silenced the voices of spring in countless towns in America?" Carson asked. She proceeded to answer the question with a frightening 366-page work that skewered DDT and its chlorinated hydrocarbon successors.

Carson pointed to the danger of DDT passing from one organism to another in the food chain and suggested that it may be "passed from mother to offspring in human milk." The book documents cases in which birds have fallen victim to the chemical after consuming worms and grubs. The author reported that DDT had been found in dead fish after the insecticide had been washed off the land into ponds and streams, and suggested that the compound would doom the eagle population. She also gives horrifying examples of people dying and falling ill after applying pesticides.

The book suffers from gross exaggeration and refutable documentation. It is interesting that in all of Silent Spring's reported cases of human deaths and illnesses, the victims — all amateurs — ignored label warnings and flagrantly applied pesticides far in excess of accepted formulas.

Silent Spring became a bestseller and foreshadowed trouble for pesticides. The effort to restrict or ban DDT gained momentum in the 1960s in the face of exhaustive hearings that pitted agricultural and chemical interests and concerned business people (including the pest control industry) against environmentalists.

As early as 1963, legislative hearings were held on the usage of DDT (the Ribicoff Hearings for the Senate Committee on Government Operations), and in 1965 the Whitten Report to the House of Represen tatives Committee on Appropriations was released. No legislative action resulted. As a consequence, however, various federal agencies, including the U.S. Forest Service and the Department of the Interior, began to eliminate and even prohibit DDT from pest control programs under their jurisdiction.

Throughout 1969 various states considered restrictions, and a one-year ban on the use of DDT was in force in Arizona. Wisconsin considered similar action, and the states of Washington, Maine, Connecticut, Montana and Michigan banned the use of DDT entirely. Within the following two years other states, including California and New York, fell in line with prohibitions against DDT and related pesticides. The forces arguing for retaining DDT by trained, judicious applicators faced insurmountable odds. Finally, the U.S. Environmental Agency sounded the death knell in holding official hearings on the continued use of DDT that lasted from August 1971 through February 1972. The findings mandated the elimination of DDT for domestic purposes as of December 31, 1973.

One irony of the situation was that in 1971, in the midst of the hearings, Dr. Norman E. Borlaug flew from his home in Mexico to testify in favor of DDT's continued use. Only a year before, Dr. Borlaug had been awarded the Nobel Peace Prize for his efforts to ease world hunger by developing of high-yield wheat strains. In his testimony, Borlaug said: "If [the cancellation of DDT] results, I have wasted my life's work. I have dedicated myself to finding better methods of feeding the world's starving populations. Without DDT ... our goals are unattainable, and starvation and world chaos will result."

The enforced demise of DDT set the stage for wide-ranging restrictions on chemical pesticides that had the environmentalists win the war. This resulted in the more restrictive Federal Insecticide, Fungicide and Rodenticide Act in 1972; certification of applicators; a federal Right-To-Know law; and the eventual widespread acceptance of integrated pest management.

As far as the structural pest control industry is concerned, in retrospect it seems both unfortunate and illogical that an industry with carefully trained operators and an excellent safety record should have been tarred with the same brush that imposed restrictions on untrained farmers, crop dusters and large-scale outdoor users. It seems ludicrous that pesticides used by PCOs on the job should be tagged as carcinogens solely on the basis of lab results that expose animals to dosages hundreds or thousands of times stronger than those applied in the field.

DDT, now a distant memory, helped win a war, saved untold lives from the ravages of disease, warded off starvation by protecting food crops, and ushered in a new era of scientific pest control. Those of us pioneers who played a role in protecting health and property with DDT during its heady days have no reason to feel anything less than pride.