POISON RESISTANT ‘super rats’ are breeding in the UK – and farmers are being asked to contribute local information to help efforts to curb their spread.

A new survey is compiling data to establish the extent to which the rat's resistance is understood, and what methods farmers are using to control rodent infestations.

Research published by the University of Reading Vertebrate Pests Unit suggests that the resistance is spreading due to the use of anticoagulants containing the actives bromadiolone and difenacoum. As these products are ineffective on resistant rodents, farmers using them are only killing rodents that have no resistance, and leaving the resistant rodents to breed with each other, which causes their numbers to increase rapidly.

The survey is being supported by BASF, where pest control specialist Helen Ainsworth said: “We believe it is important that the issue of resistance is kept fresh in the minds of farmers. Using some rodenticides in certain areas of the country could be increasing the number of resistant rodents and causing farmers to use rodenticides that are ineffective and potentially harmful to non-target species."

The survey is available to complete online until September 30, 2020, and aims to establish how often farmers are using rodenticides, which products are being used and which regions of the UK are reporting the most problems with resistance. This has been welcomed by the Campaign for Responsible Rodenticide Use that promotes best practice in the use of all rodenticide products.

“This will help to reduce the use of products that rodents have become resistant to and minimise the threat to non-target species,” said CRRU chairman Dr Alan Buckle.