Significant changes have occurred in the role of pesticides in pest management programmes since the publication of Carson's book Silent Spring in 1962. This discourse addresses the multitude of factors which contributed to these changes including such factors as policy and legislation, the public's perception of associated risks, population pressures, the availability of practical integrated pest management programmes, and perhaps most importantly, the constraints to IPM in Third World countries. While reliable statistics are difficult to obtain, the changing patterns in pesticide use in the tropical regions are also discussed. Finally, the future of pesticide use in developing countries is projected, as is the necessity of their use and expected impacts.