Which of the following is an example of a physical barrier in pest control?

A physical barrier in pest control prevents pests from accessing a specific area or target, thereby reducing damage or infestation. Traps and nets serve this purpose effectively. They physically obstruct pests from reaching plants or areas that need protection. For example, using nets over crops can keep flying insects away while still allowing light and moisture to reach the plants.

In contrast, insecticide sprays target pests directly through chemical means and do not provide a physical blockade. Fertilizers and herbicides are designed for plant growth management and weed control, respectively, but they do not act as barriers against pests. Hence, traps and nets best exemplify physical barriers in pest control.