What type of pesticide works by preventing blood clotting in pests?

Anticoagulant pesticides are specifically designed to interfere with the normal clotting process in the blood of pests. When these types of pesticides are ingested by insects or rodents, they disrupt the ability to clot blood effectively, leading to internal bleeding which is often fatal for the pest. This action targets the vascular system of the organism, making the anticoagulant an effective choice for controlling various pests, particularly rodents.

In contrast, stomach poisons work by being ingested and causing destruction of the digestive system, while systemic poisons are absorbed through the plant or body of the pest and affect the pest's physiology in other ways. Contact poisons enter through the pest's integument when in contact with it, but they do not specifically target blood clotting mechanisms as anticoagulants do. Therefore, the focus on blood clotting makes anticoagulants a distinct and specialized category of pesticide effective for certain pest control situations.