Developed countries have phased out the more dangerous chemicals, such as parathion and other organophosphates. After the US Food Quality Protection Act of 1996, several more pesticides were banned altogether, limited to farm use or further restricted to protect workers or the environment--but many are still widely used in many developing countries.
Overall pesticide use on U.S. farms dropped 0.6 percent a year from 1980 to 2007. The declines were even greater in corn fields, thanks in part to genetically modified varieties with the Bt toxin. But resistant insects have led to a recent uptick in insecticide applications. Herbicide-tolerant crops, and resistant weeds, have led to an increase in herbicide use.