Which of the following would be considered an environmental modification to control pests?

Lowering soil moisture content is considered an environmental modification because it involves altering the physical environment to create conditions that are less favorable for pest development and reproduction. Pests, particularly those such as insects and certain pathogens, can thrive in moist conditions. By reducing moisture, you can effectively decrease their survival rate and limit their population growth.

This strategy focuses on manipulating environmental factors rather than applying chemical controls or physical barriers, which is a hallmark of environmental modification. The other options involve direct pest control methods: using pesticides involves the application of chemicals, sealing off entry points creates physical barriers to prevent pest access, and setting traps targets pest capture directly. These methods do not change the environmental conditions that pests rely on for survival as effectively as altering moisture levels can.