One of the most striking examples of the pesticide treadmill is the experience of pesticide use in cotton in South/Central America in countries such as Peru and Nicaragua1. The advent of chemical pesticides in the 1950s allowed farmers to replace a diverse agricultural and ecological base with the monoculture of cotton. As conventional wisdom dictated, the farmers pursued a strategy that targeted complete pest eradication as its goal. From an economic perspective, the initial interventions were often spectacularly successful. But soon the initial successes were overwhelmed by the almost irreversible deterioration in system productivity driven by an explosion in the threat from pests.
The targeted pest developed resistance to the pesticide used and often staged a dramatic resurgence in an environment where the pesticide has often also eliminated its natural enemies. The damage done to pests’ predator species meant that the resurgence is accompanied by an outbreak of many other pests that had not been a significant threat to the crop prior to the beginning of the pesticide regime. Paradoxically, the system that started with a diverse array of crops and a few significant pests was left at the end with a monoculture of crops and a diverse array of pests. Predictably, an ever-increasing dose of pesticides need to be applied. Nicaraguan farmers who needed to spray once or twice during the season in the 50s found themselves needing to spray their crops twice a week by the 80s and eventually cotton had to be abandoned.