What is an example of a physical control measure for a pest infestation?

A physical control measure involves utilizing non-chemical methods to manage pest populations. Installing barriers or traps is a prime example of this approach, as it directly prevents pests from accessing plants or areas of concern. Barriers can include physical fences, netting, or even sticky traps that capture pests without the need for chemicals. This method is effective because it disrupts the pest's ability to reach and damage plants, thereby protecting them from infestation.

In contrast, the other options involve methods that do not fall under physical control. Chemical insecticides are chemical-based solutions aimed at killing pests, rather than preventing access. Planting resistant varieties pertains to biological control, as it involves using plants that can withstand or repel pests naturally. Applying fertilizers relates to enhancing plant health and growth, which can indirectly affect pest populations but does not constitute a physical measure against them. Each of these alternatives serves a different purpose but does not align with the definition of physical pest control.