How does a pesticide's effectiveness change over time with continuous use?

A pesticide's effectiveness can decline over time with continuous use primarily due to the development of resistance in target pest populations. As pests are repeatedly exposed to a specific pesticide, those individuals that are less susceptible may survive and reproduce, leading to a population that has a higher tolerance or resistance to that pesticide. This evolutionary pressure can reduce the overall effectiveness of the pesticide, making it less effective in controlling pest populations over time.

Understanding this phenomenon underscores the importance of integrated pest management practices, which encourage rotating different classes of pesticides and incorporating non-chemical control methods to manage resistance. Continuous use without considering the potential for resistance can lead to increased pest pressures and the need for higher doses or alternative chemicals, which are not sustainable long-term solutions. This knowledge is crucial for pesticide applicators and supervisors, as it impacts not only pest management strategies but also environmental health and safety.