What does the term "resistance" mean in pest management?

The term "resistance" in pest management refers specifically to the ability of a pest population to survive exposure to a pesticide that was previously effective. This phenomenon occurs as a result of genetic variations within pest populations; some individuals may possess traits that allow them to withstand the toxic effects of the pesticide. Over time, through natural selection, these resistant individuals survive and reproduce, leading to a population that is increasingly less susceptible to the same pesticide.

Understanding this concept is crucial for effective pest management strategies because it highlights the need for integrated pest management practices that rotate different classes of pesticides, employ cultural practices, and utilize biological control methods to reduce the likelihood of resistance developing. By doing so, pest managers aim to prolong the effectiveness of the available chemical controls and manage pest populations more sustainably.

The other options do not accurately define "resistance" in this context; for instance, adaptation to environmental changes refers to different pressures and does not specifically link to pesticide exposure, while the total number of pests is a measure of population density rather than a resistance concept. Lastly, the chemical methods used pertain to the tools employed in pest management but do not define the ability of pests to withstand those methods.