What defines a resistant pest?

A resistant pest is defined as one that is no longer controlled by a previously effective pesticide. This resistance can result from various factors, including genetic mutations in the pest population that allow them to survive exposure to the chemical, previous overuse of a specific pesticide leading to selection pressure, or incomplete application of the pesticide allowing surviving individuals to reproduce.

In practical terms, when resistance develops, it means that the expected control measures are no longer effective, making pest management more challenging and necessitating the use of alternative strategies or products. This situation can lead to the need for integrated pest management practices, including rotating different classes of pesticides, employing biological controls, or using cultural practices that can reduce pest populations effectively without relying solely on chemical interventions.

The other options do not accurately describe what constitutes a resistant pest. While using multiple pesticides can sometimes help in reducing pest populations, it does not define resistance. Adaptation to any pesticide implies broad resistance, which is not typically the case as pests may develop resistance to specific compounds rather than all. An increased pest population can occur for multiple reasons, such as favorable environmental conditions or lack of effective control measures, but it does not specifically indicate resistance.