Which of the following is NOT considered a natural control?

The concept of natural control refers to the biological and ecological factors that help regulate pest populations without the use of synthetic pesticides. This encompasses various natural elements in the environment, such as predators, parasites, and pathogens, which all play integral roles in keeping pest numbers in check through natural predation or disease.

Mechanical barriers, in contrast, do not involve living organisms and instead consist of physical structures or applications designed to prevent pests from reaching their targets. Examples include screens, nets, or traps that physically block pests from entering an area or reaching plants. While mechanical barriers can certainly be effective in pest management, they do not rely on natural biological processes, which is why they are not categorized as a form of natural control.

Thus, the identification of mechanical barriers as not being a natural control is accurate, as they represent a human-implemented strategy rather than a naturally occurring ecological interaction.