Quia California Pest Control Applicator Practice Test

The key idea here is how a pesticide reaches and affects a pest: by contact or by ingestion. Pesticides described as contact killers act when the pest touches or crosses a treated surface, so death comes from exposure at the exterior or on contact with the treated area. In contrast, stomach poisons must be eaten or ingested by the pest; the poison works from inside the gut after feeding, often through a disruption of digestion or internal systems. Because of that difference in exposure route, they’re used in different ways—surface sprays and residues for contact effects, and baits or treated foods for stomach poisoning. The statement that contact pesticides kill by contact with treated surfaces while stomach poisons require ingestion correctly captures this distinction. The other options misstate the required exposure route or imply identical mechanisms, which isn’t accurate.