Which method can be used to reduce pest populations without pesticides?

Genetic engineering is a method that can effectively reduce pest populations without the use of traditional pesticides. This approach often involves modifying the genetic makeup of plants or pests to enhance resistance to pests or diseases. For example, scientists can develop genetically modified crops that produce natural toxins harmful to specific pests, thereby reducing the need for chemical interventions.

This method also holds the potential to minimize the overall impact on the environment and non-target organisms while providing a more sustainable solution to pest management. By focusing on modifying the traits of the organisms involved, genetic engineering aims to create an ecological balance that reduces pest populations naturally.

In contrast, the other options listed involve either direct chemical interventions or practices that can exacerbate pest problems, which is why they are less aligned with reducing pest populations sustainably without the use of pesticides.