In a J.R. Geigy laboratory in the late 1930s, Paul Hermann Müller formulated a compound that would revolutionize the pest control industry.
Müller’s synthesis of dichlorodiphenyltrichloroethane (DDT), the first modern contact insecticide, would play a major role in combating diseases of World War II, controlling insect pests on crops and in homes, and controlling life-threatening insect-borne diseases in developing countries.
Even though the compound was phased out in most industrialized countries in the 1970s, it paved the way for modern, effective alternatives.
Müller born in Solothurn, Switzerland, in 1899, began his career in industrial chemistry at Dreyfus and Co and Lonza AG before returning to Switzerland’s Basel University to earn his Ph.D in 1925.
After earning his degree, he began work at J.R. Geigy AG, a dye synthesis company, in Basel. He would continue at Geigy, eventually becoming deputy director of scientific research on substances for plant protection in 1946.
A Strasburg student had first synthesized DDT in 1874, but Müller was the first to discover its insecticidal properties. Müller working on synthetic contact insecticides for moth control, independently resynthesized DDT and tested it against houseflies, lice, Colorado beetles and mosquitoes.
Müller who would receive the Nobel Prize for his project, said in his Nobel acceptance lecture that at the time of his work with DDT, he was researching effective, low-cost agricultural insecticides because few were commercially available.
“Only a particularly cheap or remarkably effective insecticide had any prospects of being used in agriculture since the demands put upon an agricultural insecticide must be strict,” he said. “I relied on my determination and powers of observation. I considered what my ideal insecticide should look like, and the properties it should possess.”
Müller conducted lab testing on various formulations in order to meet his goals of a product with high toxicity, rapid onset of toxic action, little or no mammalian or plant toxicity, a wide range of action, persistence and low cost.
“It was not easy to discover a good contact insecticide,” he said in his speech. “In the field of natural science, only persistence and sustained hard work will produce results, and so I said to myself, ‘Now, more than ever, must I continue with the search.’”
His four-year research process on DDT led to a Swiss patent in 1940. Two DDT-based products, Gesarol and Neocide, first became available in 1942. Müller’s goal was to create a contact insecticide for agricultural use, but it also found application in hygiene, textile protection and stored products.
DDT entered the market as British and American medical entomologists were looking for alternatives to combat pests in war zones because pyrethrum stores were falling short of demand. One account says that Swiss researchers, recognizing the efficacy of DDT, secretly shipped a small batch to the United States. U.S. researchers confirmed its insecticidal properties and began speedy production for war use.
Hailed by many as a miracle, DDT combated insect-borne diseases like typhus and malaria. Müller’s compound was inexpensive to produce, widely available, strong and persistent, and apparently safe. Soldiers used it to kill lice and mosquitoes, and it was effective in crop protection.
DDT proved its mettle in October 1943 during a heavy typhus outbreak in Naples, Italy. General Leon Fox, physician to the American forces, introduced DDT treatment to the area. For the first time in history, an outbreak was controlled in winter.
Malaria was completely eradicated from several islands, and World War II became the first war in which more people died from casualties than from disease.
After the war, DDT spread to civilian uses. It was so effective that pest management professionals worried homeowners would no longer need professional services. This prompted the National Pest Control Association (NPCA) to encourage PMPs to diversify their businesses and step up to the challenge.
PMP’s “now have an obligation to practice preventative pest control wherever possible,” then-NPCA Executive Secretary Bill Buettner told the industry.
“It’s not enough to sit back and wait for infestations to develop,” he said. “Clients know it takes intelligent handling of the newer pesticides to do a satisfactory job. It is up to [PMPs] to fulfill this expectation without endangering the lives or health of the public.”
Other organizations also noticed the impact DDT had on public health. In 1948, the Nobel Foundation awarded Müller’sthe Nobel Prize in physiology or medicine.
In his introduction of Müller at the Nobel awards, Prof. G. Fischer, member of the Staff of Professors of the Royal Carolina Institute, said this: “Without a reasonable slice of luck, hardly any discoveries would be made. But the results are not simply based on luck. The discovery of DDT was made in the course of industrious and certainly sometimes monotonous labor. The real scientist is he who possesses the capacity to understand, interpret and evaluate the meaning of what at first sight may seem to be an unimportant discovery.”
The U.S. government phased out DDT in the 1970s following discoveries that its persistent toxicity had long-term adverse effects on mammals, birds and the environment. Today, however, its controlled use in developing countries still keeps insect-borne diseases like malaria in check.