Why might a pest be considered tolerant to a pesticide?

A pest may be considered tolerant to a pesticide when it has developed resistance methods, meaning that over time, through natural selection, certain individuals within a pest population acquire traits that reduce the effectiveness of the pesticide. These resistance methods can involve physiological or behavioral changes that enable the pest to survive exposure to the chemical treatment that would normally be lethal. For example, the pest might produce enzymes that break down the pesticide or alter its target site so that the pesticide no longer binds effectively.

Understanding this concept is critical in pest management because it highlights the importance of rotating different modes of action in pesticide use to prevent the pests from adapting and becoming more challenging to control.