What type of pesticide acts by killing insects on contact?

• A. Systemic insecticides
• B. Contact insecticides
• C. Granular insecticides
• D. Residual insecticides

Answer: (B)

Contact insecticides are specifically designed to kill insects upon direct contact. These pesticides work by affecting the insect's nervous system or causing physical harm immediately when they come into contact with the target pest. Unlike systemic insecticides, which are absorbed and affect the insect internally after ingestion, contact insecticides offer a quicker knockdown effect by targeting the surface of the insect's body.

Granular insecticides, while they may also kill insects, typically require ingestion by the pest rather than simply contact. Similarly, residual insecticides are meant to remain active on surfaces for a certain period, but their action primarily depends on contact over time rather than immediate effects.

Understanding the specific action of contact insecticides is crucial for effective pest management, as they are often utilized for fast eradication in situations where immediate control of a pest population is necessary.