CHAPTER 2:Classical Insecticides: Past, Present and Future

We present an historical review of the use of classical insecticides, as examples of non-green agrochemicals that must be replaced and their use reviewed. The chapter is divided into two main sections; in the first, the approaches used for insect control before the development of synthetic insecticides are covered. The use of non-rational insecticides, mainly from mineral sources (e.g. sulphur, arsenicals, copper, or boron derivatives) and lacking specificity in most cases is widely reviewed.The second part of the chapter is focused on the three main families of synthetic insecticides that have dominated the agrochemical sector from the 1940's to nowadays: organochlorine, orgaphosphorus and carbamates. Their syntheses, relative toxicity, selectivity and environmental fate are included.The high efficiency and economic viability of such compounds allowed an indiscriminate use in crops, household and cattle. Nevertheless, it is strongly highlighted along this chapter that many of such insecticides are bioaccumulated or provoke severe toxicological effects in mammals, fishes and beneficial insects such as bees. It is also discussed the restrictions and bans exerted by the most recognized organizations such as the US EPA, European Union's Committees, or the World Health Organization for reducing or even eliminate their use.