Use of chemical inputs such as pesticides has increased agricultural production and productivity. However, negative
externalities from such use have increased too. These externalities include damage to agricultural land, fisheries, fauna
and flora. Another major externality is the unintentional destruction of beneficial predators of pests thereby increasing
the virulence of many species of agricultural pests. Furthermore, increased mortality and morbidity of humans due
to exposure to pesticides are recorded especially in developing countries. The costs from these externalities are large
and affect farmers’ returns. However, despite these high costs, farmers continue to use pesticides and in most
countries in increasing quantities. In this paper, we examine this paradox and show why farmers continue to use
pesticides despite the increasing costs. We also emphasize ‘lock-in’ aspects of pesticide use. © 2001 Elsevier Science
B.V. All rights reserved.