Which of the following is a biological control method for roaches?

• A. Sterile males
• B. Parasitic wasp
• C. Habitat modification
• D. Bacteria

Answer: (B)

Biological control uses living organisms to reduce pest populations. A parasitic wasp is a natural enemy of roaches, meaning it attacks them and, through its life cycle, helps lower their numbers. The wasp may lay eggs in or on roaches or their eggs, and the developing offspring ultimately kill the host. This directly reduces the pest population with minimal chemical intervention and can provide long-term suppression as the wasp populations persist in the environment.

While other options involve different approaches—habitat modification is a cultural or physical strategy, and bacteria would rely on microbial pathogens that are not the classic form of biological control for roaches—the parasitic wasp embodies the concept of using a living organism to directly temper pest numbers. The sterile-male approach is another method, but it falls into genetic control rather than utilizing a living enemy that actively harms the pest population.