What are beneficial insects known for in pest control?

Beneficial insects play a crucial role in pest control primarily by eating or developing inside pest insects. This behavior is essential for managing pest populations naturally. Predators such as ladybugs, lacewings, and certain wasps feed on aphids, caterpillars, and other harmful insects, effectively reducing their numbers in the environment. Additionally, some beneficial insects lay their eggs inside or on pest insects, leading to the larvae consuming their hosts.

The function of beneficial insects extends beyond mere consumption; they help sustain a balanced ecosystem and minimize reliance on chemical pest control methods. Their activity not only helps keep pest populations in check but also contributes to the overall health of agroecosystems.

In contrast, the other options highlight activities that do not contribute positively to pest control. Eating plant roots and bushes can harm plants directly, while damaging landscape plants disrupts the growth and health of vegetation. Competing for nutrients may influence pest populations but lacks the direct pest control efficacy that predation or parasitism provides. Thus, the correct answer emphasizes the direct impact beneficial insects have on controlling pest populations through their predatory and parasitic behaviors.