An insect killed after crawling over an insecticide residue on a surface is an example of which type of control?

• A. Direct contact
• B. Systemic
• C. Indirect contact
• D. Physical

Answer: (C)

Exposure routes determine how pest control works. When an insect dies after crawling over a surface that has been treated with pesticide residue, it was killed by coming into contact with the chemical on that surface. This is indirect contact because the pest didn’t receive a direct application to the insect itself; the pesticide is on the environment and acts when the pest touches it.

Direct contact would be the pesticide applied directly to the insect (for example, spraying or dousing the pest). Systemic pesticides rely on the pest ingesting or absorbing the chemical through a host that has taken it up (like a plant or other carrier), which isn’t the case here. Physical methods are non-chemical strategies such as traps or barriers, not chemically mediated kill.