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Therefore, it made sense to produce more food than needed by the family and ship the excess to urban
markets. This, increasingly, became easier because farmers were moving from horse-drawn cultivators
to increasingly sophisticated tractors and could plow more acreage in shorter periods of time. Also, it
became clearer that it was more profitable to concentrate on fewer cash crops such as corn and wheat. In
fact, by the 1950s and 1960s, entire regions specialized in producing one cash crop (Recall, this practice
actually had begun in the 1800s with cotton and potato). However, moving to a monoculture agricul-
tural system meant that insects feeding on these crops now had vast areas of unbroken fields of their
preferred hosts, obviously an unnatural ecosystem. What, was needed, therefore, was better insecti-
cides. But, all that was available at that time were arsenicals, sulfur, kerosene, mineral oil emulsion,
naphthalene, paradichlorobenze, nicotine sulphate, and rotenone, all of which were largely ineffective.
This began to change in the late 1930s with the advent of synthetic organic insecticides (Reinhardt
and Ganzel 2003).
16.2.2 Age of Synthetic Organic Insecticides (Chlorinated
Hydrocarbons, Organophosphates, Carbamates)
The age of commercial use of synthetic organic insecticides began in the 1940s with the advent of DDT
(Dichlorodiphenyltrichloroethane). DDT was first synthesized in 1873 by Othmar Zeidler, an Austrian
chemist, who did not investigate its properties and, therefore, did not recognize its potential as an insec-
ticide (Ware 1994, Pedigo and Rice 2015). This discovery was made approximately 65 years later by
Paul Hermann Müller, a Swiss chemist, working for J. R. Geigy AG. He had been assigned to develop
an insecticide and was looking for an ideal contact insecticide that would have a quick and powerful
toxic effect upon as many insect species as possible (broad spectrum) but would cause little or no harm
to plants or warm-blooded animals. He also wanted to develop an insecticide that had a long residual
action with high chemical stability and was cheap to produce. He had two primary motivations: (1) a
severe food shortage in Switzerland, which could be lessened by a better way to control insect infestation
of crops, and (2) the presence of a typhus epidemic, carried by head and body lice, in Russia, the most
extensive and lethal epidemic in history (1918–1922) (Patterson 1993). He began his search in 1935.
Müller worked for 4 years on his project, testing numerous compounds and failing 349 times. But,
in September 1939, he found what he had been looking for, DDT. He placed a fly in a cage with this
insecticide and, shortly thereafter, the fly died. Subsequently, DDT was tested by the Swiss government
and the United States Department of Agriculture against the Colorado potato beetle and found it to be
highly effective. Subsequent work showed that DDT was effective against a wide range of pests including
sand flies, mosquitoes, fleas, and lice known to transmit, respectively, various tropical diseases, malaria,
plague, and typhus. And, because DDT’s discovery coincided with World War II and the presence of
disease among the troops, DDT was used to protect the Allied Forces from these blood-sucking insect
vectors (Pedigo and Rice 2015).
After the war, DDT was offered commercially for general use by the public on farms, orchards, and
in and around homes. In fact, DDT was used in sprays, paints, wallpaper, dusts for pests, and many
other formulations. It seemed to be the perfect insecticide because, at the time, all information about
it was positive. For the next 20–25 years, DDT and other chlorinated hydrocarbons were used and
overused indiscriminately. As Smith and Kennedy (2002) stated so succinctly, “Such optimism had a
profound effect on the crop protection sciences. In entomology and weed sciences especially, research
shifted focus away from pest biology on to pesticide technology. At this point, the birthright of pest
control scientists as biologists became endangered.” As reliance on pesticides increased, the simple
question of whether or not a pesticide application was even necessary or justified economically led
Doutt and Smith (1971) to coin the term “pesticide syndrome.” Applications were based on the calendar
rather than on the pest populations. Pesticide manufacturers encouraged farmers to view premature
applications as protection from pest problems before they appeared and, typically, this was referred to
as “preventive control.”
By the late 1950s and the 1960s, concerns were emerging about the negative effects of pesticides
on the environment. Examples included resurgence of pest populations because of elimination of their
natural enemies, outbreaks of secondary pest populations that had been held in check by populations