Irish Rodenticide Resistance Project


Resistance to the anticoagulant rodenticides is a growing problem in the EU. There is evidence of resistance to anticoagulants, including bromadiolone and difenacoum, in Belgium, Denmark, France, Germany, The Netherlands and Hungary.

In the UK, within a few years of the arrival of difenacoum and bromadiolone on the market, populations of Norway rats resistant to either difenacoum or bromadiolone, or both, were being identified, particularly in central southern England. Subsequently, individual sites with resistance to either difenacoum and/or bromadiolone were identified during the 1980s and 1990s in a number of areas including East Anglia, Yorkshire and Lincolnshire.

In several countries there are multiple resistance genotypes and some of these confer resistance to some of the less-potent second-generation anticoagulants.   Resistance to anticoagulants in house mice is also likely to be widespread in many EU countries, both to the first-generation active substances and to some of the second-generation. The fact that resistance has not been found in some EU Countries does not mean that it does not exist in them.
The Irish rodenticide resistance project has now been set up and will begin genetic sampling of rats and mice to gather data on the existence of the resistant gene in Irish rodents. This project will be operated with the assistance of the Department of Agriculture Food and the Marine. IPCA members will play a large part in this project. The first pilot study will be carried out in Dublin, Meath and Kildare before the end of 2015.
Using anticoagulant rodenticides which are ineffective poses a severe threat to non-target animals and wildlife in general. It is also a threat to the effectiveness of your rodent control strategies.