ABSTRACT
From the 1860s until the advent in 1942 of DDT (1-chloro2-[2,2,2-trichloro-1-(4-chlorophenyl)ethyl]benzene), there were numerous inorganic and naturally occurring compounds (inorganic and organic components extracted from plants and animals) developed and used for control of insects and plant diseases, particularly fungi. Little progress occurred in the discovery of natural or chemical means to control weeds. The chemistry of arsenicals was further exploited to control insects (Paris Green [copper(II) acetoarsenite]). Bordeaux mixture (copper sulfate and lime) was found to be extremely useful in the control of plant diseases, leading to its widespread usage. The invention of the pressure sprayer (both hand and power driven) made efficient large-scale application of pesticides feasible and economical. Aerial application was also invented (in the early 1920s), leading to expanded applications in agriculture. The availability of DDT, beginning in 1945 for civilian/agricultural usage, opened a new era of pest control, leading not only to its extensive usage but also to the development of numerous other synthetic organic insecticides, for example, organophosphates in 1946. About two years earlier in 1944, selective synthetic organic herbicides were discovered, starting with 2,4-D (2,4-dichlorophenoxyacetic acid), which revolutionized weed control in agriculture and elsewhere. Also, synthetic organic fungicides (metal based) were developed as effective controls of plant diseases (and for other applications). During the 1950s and 1960s, granular pesticide formulations were developed, which led to large expansions of pesticide usage on major field crops [Aspelin (21A02)].
