Which method can promote effective biological control?

Promoting effective biological control relies on creating environments that support and sustain natural enemies of pests, such as predators and parasitoids. Habitat enhancement involves fostering conditions that attract and maintain these beneficial organisms, providing them with food, shelter, and suitable breeding sites. This method helps improve the presence of natural predators that can keep pest populations in check through their natural predation behaviors.

Using synthetic pesticides exclusively, as mentioned in one of the choices, can disrupt the balance of the ecosystem by killing not just the target pests but also their natural enemies. This can lead to pest resurgence as the predators that would normally help control pest populations are eliminated.

Planting only non-native species could lead to disruptions in local ecosystems and may not support the native natural enemies effectively. These non-native plants might not provide the necessary resources (like nectar and pollen) that the local biological control agents need to thrive.

Monitoring pest activity without intervention can help in understanding pest dynamics and population thresholds, but without taking action to enhance biological control, this strategy leaves pest populations unchecked. Effective biological control goes beyond observation to actively promoting the factors that support pest-enemy relationships.