Which method is least likely to be used in mechanical pest control?

Mechanical pest control relies on physical methods to manage pest populations, rather than chemical interventions. Using traps, applying barrier methods, and configuring physical barriers are all direct physical means of preventing or reducing pest access and establishing control. These methods do not involve the use of chemicals, making them distinctly part of mechanical control practices.

In contrast, implementing chemical sprays introduces substances specifically designed to kill or repel pests, which falls outside the realm of mechanical control. The essence of mechanical pest control is to use physical means rather than relying on chemical solutions, thus making the use of chemical sprays the least aligned with mechanical pest control practices.