Rodenticides

Rodenticides are toxic chemicals used to kill rodents, primarily rats and mice, to protect crops, food stores, and structures. They are formulated as baits, blocks, pellets, granules, or liquids and delivered in stations or placed in rodent tunnels. They work by destroying the animal's physiological systems or metabolism after ingestion.

Most commonly used are anticoagulant rodenticides, which interfere with vitamin K recycling and prevent blood clotting, leading to internal bleeding. These include first-generation compounds such as warfarin and difenacoum and second-generation compounds such as bromadiolone and brodifacoum, which can be more potent and require fewer feedings. Non-anticoagulant rodenticides include cholecalciferol (vitamin D3), bromethalin (a neurotoxin), and zinc or aluminum phosphide, which act through different mechanisms and can cause rapid death.

Rodenticides are typically regulated products. Some require professional applicators and restricted sale, with labeling that details species, dosage, placement, and required safety precautions. When used, baits should be placed in tamper-resistant stations to limit exposure to children and non-target animals, and cleaning and disposal should follow label instructions.

Risks include toxicity to non-target wildlife, domestic pets, and accidental secondary poisoning of predators that consume poisoned rodents. Environmental concerns emphasize careful placement, prompt cleanup of spills, and avoidance near water sources. Resistance to anticoagulants has been observed in rodent populations, necessitating rotations and integrated pest management.

Alternatives include sanitation, sealing access points, traps, and habitat modification, as well as non-chemical controls. Integrated pest management aims to reduce rodent pressure while minimizing chemical use.