The Rodenticide Resistance Action Group (RRAG) has published updated versions of their rat and mouse resistance guidelines here.
A key addition is inclusion of the non-anticoagulant cholecaciferol and its role in resistance management.
Further additions include consideration of new resistance data such as ‘hybrid resistance’, updated information on the distribution of resistance, and a useful appendix that classifies active ingredients for resistance management.
The text “It would therefore be prudent, in areas where resistance in house mice is suspected, not to use products that contain difenacoum” deserves attention. Knowing about the current prevalence of resistance in UK house mice (93.5% of samples), and the fact that this is widespread on maps, there are likely to be no places where difenacoum resistance in house mice is not ‘suspected’.