The problems of controlling insects and other pests have reached an all-time high. Pest control researchers, extension specialists and farmers are faced with mounting pest problems while certain avenues to solutions are meeting constraints of a technical, economic or social nature. These problems include: the damaging effects of persistent pesticide residues on terrestrial fresh water and marine organisms; the destruction of beneficial controlling organisms, thereby causing an increase in the number of pest species and their abundance; and the development of pest strains resistant to the pesticides used to control them. This resistance has in turn led to use of a still greater variety of pesticides and their use in greater quantities. In some situations it has become uneconomic even to attempt to control certain crop pests, and large areas have suffered great economic and social stress.
The global use of agricultural pesticides rose from about 50 million kilograms a year in 1945 to current application rates of approximately 2.5 billion kilograms per year. Most modern pesticides are more than 10 times as toxic to living organisms than those used in the 1950s.
Cotton bollworms were not a big problems until farmers decided to spray them. Most of the bollworms were controlled by natural predators. With the use of pesticides the predators were killed.