Insecticides – DDT +
“DDT – Our War Famed Bug-Killer.”
“This Joe Louis of the Insecticides.”
Those were the headlines that greeted readers of Nebraska Farmer magazine in 1946. Obviously, DDT was an unqualified success in initial trials of the poison.
In the July 6, 1946 issue of the magazine, Keith Carter wrote, “After winning a glorious victory during the World War II over the insidious insect foes of G. I. Joe, DDT has shucked its military clothes, wrapped up its world-wide service bars, and come back home to take over the No. 1 spot in America’s bug battle.”
The chemical was popular for several reasons:
- It killed a wide range of insect pests, in other words it had a “broad spectrum” impact.
- It was persistent, meaning it didn’t break down in the environment so it didn’t have to be reapplied too often.
- It did not wash off in water, that is, it was “insoluble.”
- It was relatively cheap and easy to apply.
In April 1946, Nebraska Farmer carried an article by University of Nebraska entomologist – a “bug-killing authority” – Don Whelen who had served for 18 months as an Army entomologist, presumably battling the carriers of malaria and typhus. In his article, Whelen outlined over a dozen different uses for DDT on the farm and in the home while only briefly mentioning that “other [entomologists] feel that it still needs further experimentation in order to work out proper dosages or safeguards.”
With that one note of caution, Whelen outlined ways to use DDT as a spray or dust on livestock, in the garden or in the house. He wrote that the insecticide could rid a house of flies, fleas, roaches, ants and bed bugs. He noted that DDT could be sprayed from airplanes and that “it is probably out of the question to absolutely rid a town of flies by spraying with DDT but it is not impossible to greatly reduce the number of flies so that they will hardly be noticed.”
Later that year, Nebraska Farmer reported that a year’s worth of testing on livestock had shown huge profits from the product.
“Carefully controlled tests with 8,000 head of cattle showed that spraying or dipping with DDT through the fly season improved the gains of beef cattle on pasture an average of one-half pound a day per head. At that rate, the improved gain for the DDT treated cattle averaged 50 pounds a head in a 100-day season. For the entire 8,000 head it meant 400,000 pounds more beef produced at a cost of some labor and a little money.”
The article went on to report results in dairy herds. “The treatment indicated that knocking out the flies would improve the flow of milk by 15 percent.”
Weight gains of 400,000 pounds in a herd and 15 percent more milk were huge numbers that few farmers could ignore. DDT sales took off, and the government quickly had to step in and require accurate labeling of the strength and contents of DDT products.
With the labeling, research and promotion, sales of DDT rose from $10 million in 1944 – mostly for military use – to over $110 million in 1951, mostly for agricultural use.
More and more uses were promoted. One company advertised “Carbola-DDT Disinfecting White Paint.” In barns, this paint did “Three Necessary Jobs … in one easy lower cost operation: 1) Kills flies 2) Kills disease germs 3) Gives white walls.” We don’t know if the paint was ever used inside a farmer’s house.”
Research sponsored by the USDA (U. S. Department of Agriculture) kept discovering more and more crops that could be saved. A few studies showed the chemical was ineffective against some pests, but by this time, the techniques used to synthesize DDT had shown chemists how to formulate related insecticides. DDT is an “organochlorine,” meaning it’s based on carbon (organo) and contains chlorine and hydrogen. Within a few short years after the war, chemists had formulated other organochloride compounds with amazing names, like chlordane, toxaphene, heptachlor and dieldrin. Other chemists were working with the cousins of DDT known as organophosphates. The insecticides produced included parathion and malathion. There were literally thousands of new chemicals coming to the market promising to control specific insect pests.
These developments were nothing short of a chemical revolution in the fight against pests. In 1946, the USDA announced a study that showed that “Combinations of new organic insecticides provide control of all major cotton insects for the first time.” [emphasis added.] Three years later, the USDA announced another first – “Grasshopper control by individual farmers is possible for the first time by use of chlordane or toxaphene in sprays, dusts, or baits.”
Kelly Holthus remembers when DDT was sprayed throughout his rural community of Loomis, Nebraska, to control mosquitoes. “Everybody liked DDT because they really got a kill. They didn’t know the rest of the story.”
Yet, as early as 1946, one USDA study buried in the mix discovered that some flies were becoming resistant to DDT, and substitute materials had to be recommended.
In 1949, the first government study to raise health concerns for humans was published. The study found DDT traces in the milk of cows sprayed with the chemical. “Safe alternative substitute insecticides” were recommended to control flies and lice on cattle because the economic impact of a reduced milk production was too high a cost for most dairy farmers to forego insecticide use. The USDA warned milk producers not to use DDT on dairy cattle, but it did not even consider banning the chemical.