A pesticide applicator should vary the types of pesticides used on a target pest to:

The reasoning behind varying the types of pesticides used on a target pest is primarily to minimize pest resistance to the pesticide. When a single type of pesticide is repeatedly used, pests can adapt and develop resistance over time. This resistance can lead to more significant infestations, making it increasingly difficult to control the population with the same chemical.

By using a variety of pesticides, each with different modes of action, an applicator can reduce the likelihood of pests developing resistance. This approach not only prolongs the efficacy of existing pesticides but also enhances the overall effectiveness of integrated pest management strategies. Utilizing a diverse arsenal of pesticides contributes to continued success in controlling pest populations and helps maintain the integrity of pest management programs.