Which of the following best describes mechanical control strategies?

Mechanical control strategies refer to the use of physical methods to manage pest populations without the application of chemicals. This approach can include actions such as trapping, mowing, tilling, or using barriers to prevent pests from causing damage. By employing these physical means, mechanical controls aim to reduce pest numbers or damage directly.

The other options do not accurately represent mechanical control strategies. For instance, using machinery to increase pest populations contradicts the goal of control, while the application of chemicals is associated with chemical control methods rather than mechanical ones. Monitoring for pest thresholds is part of an integrated pest management regime that helps determine when control measures are necessary but does not itself fall under mechanical control.