Which of the following management strategies is focused on using natural predators to control pest populations?

The focus of the correct answer lies in the use of natural predators as a method of pest management, which is the essence of biological control. This approach harnesses the existing ecosystem by introducing or promoting organisms that naturally prey on pests, effectively reducing their populations without relying on synthetic chemicals.

Biological control strategies can include the release of parasitoids, predators, or pathogens that specifically target the pest species. This method not only minimizes the use of chemical pesticides, which can have adverse environmental effects, but also promotes biodiversity and sustainable practices in managing pest populations.

Other strategies mentioned, such as pesticide treatment, involve the application of chemicals to directly eliminate pests, which does not utilize natural or biological interactions. Cultural practices modify the environment—like crop rotation or habitat management—to discourage pest infestation but do not directly involve natural predation. Mechanical removal involves physically removing pests from an area and also does not engage natural predators for ongoing control. Thus, biological control stands out distinctly as the strategy that directly utilizes and relies upon nature to manage pest populations.