ABSTRACT

Early man used to protect crops from herbivores with homemade remedies. As agricultural practices evolved, these remedies were replaced by insecticides of plant origin. The introduction of DDT in 1939 was considered a panacea for all ills. The introduction of carbamates, chlorinated hydrocarbons, organophosphates soon followed. However, these organic pesticides soon started posing serious problems of insecticide resistance, toxic residues, and the resurgence of non-target pests. Rachel Carson shared all the ill-effects of organic pesticides in her book, Silent Spring. Another group of pesticides, synthetic pyrethroids, were introduced in the early 1980s to control cotton bollworms. Soon the efficacy of this category of insecticide faded away as these chemicals caused a resurgence of whiteflies. This insect developed resistance to a large number of insecticides, leading to large-scale outbreaks throughout the world. Even when neonicotinoids were introduced to check the menace of sucking pests, the large- scale resistance to neonicotinoids in whiteflies was another worrisome point. In the year 2002, Bt cotton was introduced to check the menace of bollworms. It provided a further boost to the whitefly build-up. The reasons for the build-up of whiteflies were mainly the parthenogenetic reproduction without males (haplodiploid arrhenotoky), its polyphagous nature, the cultivation of susceptible germplasm, suitable climate, and the introduction of Bt kinds of cotton, among many more in the list. The new molecules, namely spiromesifen, spirotetramat, chlorantraniliprole, flubendazole,difenthiuron, flonicamid, buprofezin, etc. are available with a different mode of action and their safety to non-target animal fauna. These should be utilized as a part of integrated pest management.