Which method is not considered a mechanical control for pests?

Mechanical control methods are techniques used to manage pest populations through physical means rather than the use of chemicals. In the context of this question, the installation of screens, vacuuming for cockroach control, and the use of light traps all involve physical methods to prevent or eliminate pests directly.

The application of chemicals, on the other hand, relies on the use of pesticides or similar substances to kill or repel pests, which categorizes it as a chemical control method. Thus, it does not fit within the definition of mechanical control, as it does not involve any physical manipulation of the pests or their environment to reduce their numbers. Understanding these distinctions is crucial in pest management practices to effectively choose the appropriate control methods for different situations.