A Guide to Rodenticide Active Ingredients
Rodenticides contain different active ingredients, each working in a particular way. Understanding these differences helps pest control professionals select appropriate products and manage risks to wildlife, pets and people.
Non-Anticoagulant Rodenticides
Alphachloralose
Alphachloralose acts on the nervous system, causing sedation and reducing body temperature. It is primarily used to control house mice. Effectiveness can be influenced by environmental temperature. Always check the product's approved use conditions.
Cholecalciferol
Cholecalciferol, also known as vitamin D3, disrupts calcium regulation in rodents. It offers an alternative mode of action to anticoagulants and may be useful where anticoagulant resistance is a concern. It remains hazardous to non-target animals.
First-Generation Anticoagulants
Anticoagulants interfere with vitamin K recycling, preventing normal blood clotting. First-generation ingredients generally require repeated feeding to achieve a lethal effect.
Warfarin
Introduced during the 1950s, warfarin was one of the earliest anticoagulant rodenticides. Resistance developed in some rat and mouse populations, reducing its effectiveness.
Coumatetralyl
Coumatetralyl is another first-generation anticoagulant. Its effectiveness can be reduced by anticoagulant resistance, making local resistance information important when considering suitable control methods.
Second-Generation Anticoagulants
Second-generation anticoagulant rodenticides (SGARs) were developed to address resistance to earlier products. They are generally more potent and persistent, increasing potential risks to non-target wildlife.
Difenacoum
Introduced in the 1970s, difenacoum has been widely used against rats and mice. Resistance in some UK rodent populations can reduce its effectiveness.
Bromadiolone
Bromadiolone is used for rat and mouse control. Like difenacoum, its effectiveness varies where resistant rodent populations are present.
Brodifacoum
Brodifacoum is a highly potent second-generation anticoagulant. Its persistence in animal tissues presents particular risks of secondary poisoning to predators and scavengers.
Flocoumafen
Flocoumafen is another highly potent second-generation anticoagulant. It can be effective against some resistant rodent populations but requires careful management of environmental and non-target risks.
Rodenticide Resistance and Responsible Use
Anticoagulant resistance occurs when inherited genetic changes reduce a rodent's susceptibility to certain active ingredients. Repeated ineffective treatments can increase environmental exposure without achieving control.
Always assess the infestation, consider non-chemical methods and follow the current product label. Authorised species, locations and user categories vary between products.
For further guidance, visit CRRU UK – Think Wildlife.
