What type of pesticide is designed to be effective when ingested by pests?

A stomach poison is specifically designed to be effective when ingested by pests. This type of pesticide targets the digestive system of the pest. When the pest consumes the bait or treated material containing the stomach poison, it disrupts their normal physiological processes, ultimately leading to death. This method of action takes advantage of the feeding behavior of pests, making it a targeted approach to pest management.

In contrast, contact pesticides work by directly affecting the pest when they come into contact with the treated surface or material, rather than through ingestion. Fumigants are gaseous pesticides that penetrate through tissues when pests breathe them in, working primarily through gaseous exposure rather than ingestion. Systemic pesticides are absorbed by the plant and circulate through its tissues, affecting pests that feed on the plant, but they do not function primarily as stomach poisons since their effectiveness is related to uptake by plants rather than direct ingestion by the pest.