What type of pesticide is known as a stomach poison?

The definition of a stomach poison refers specifically to a type of pesticide that has to be ingested by the pest in order to be effective. This means that the active ingredients are toxic when consumed, affecting the pest's digestive system and ultimately leading to its mortality.

Pesticides that fall into this category are formulated to attract pests, encouraging them to consume the bait containing the chemical, which is what makes them particularly effective against certain insects or rodents. This mode of action is critical for certain types of pest management, especially in situations where contact pesticides may not be effective because the pest does not come into contact with the pesticide directly.

The other types of pesticides mentioned do not fit the definition of a stomach poison. For instance, contact pesticides work only when they touch the pest and do not need to be ingested. Pesticides that target soil pests or those effective against flying insects may operate through different mechanisms altogether, such as disrupting their respiratory systems or creating a barrier that prevents movement rather than through ingestion. Therefore, the correct answer highlights the unique action of stomach poisons among the various classes of pesticides.