Which of the following is a mechanical control method in pest management?

Mowing is considered a mechanical control method in pest management because it physically removes pests and their habitats. By cutting down weeds and overgrown vegetation, mowing helps to disrupt the life cycles of pests that may inhabit those areas. This action reduces the available food and shelter for pests, making it an effective way to manage pest populations without the use of chemicals.

Other choices involve chemical or biological approaches. Herbicide application directly involves chemicals to kill plants, and soil fumigation involves the use of chemical agents to target pests in the soil. Planting resistant varieties focuses on breeding or selecting plants that can withstand pests or diseases, which leans more toward a biological control than a mechanical one. Thus, mowing stands out as the only option that utilizes a physical method to control pest populations.