Pesticide Usage in Scotland: Rodenticides on Arable Farms

Appendix 3 - Definitions and notes

1) Rodenticide is used throughout this report to describe a substance used to kill or control rodents.

2) An active substance is any substance which has a general or specific action against harmful organisms. In this report this refers to a substance with a detrimental effect on rodents.

3) The term product is used to describe a marketed rodenticide product which contains active substance(s), bait and other co-formulants.

4) The term formulation is used to describe an active substance or mixture of active substances formulated together in a product. A formulation is not synonymous with a product; the same formulation of active substances is present in many different products.

5) Rodenticides are classified as anticoagulant (which prevent the synthesis of blood clotting factors resulting in rodent death by haemorrhage) or non-anticoagulant compounds. The anticoagulant rodenticides are classified into first and second generation compounds (FGARs and SGARs respectively). The FGARs, which were the first anticoagulant compounds to be developed, are less acutely toxic than SGARs.

6) The rodenticides approved for use in the UK during the 2022 survey period were: FGARs (coumatetralyl and warfarin), SGARs (brodifacoum, bromadiolone, difenacoum, difethialone and flocoumafen) and non-anticoagulant rodenticides (alphachloralose, cholecalciferol, aluminium phosphide, carbon dioxide and hydrogen cyanide). The rodenticides encountered in this survey were; alphachlorolose, brodifacoum, bromadiolone, coumatetralyl, difenacoum, flocoumafen and difethialone.

7) The term holding is the basic unit used in the agricultural census and, in this report, is synonymous with the term 'farm'. In this survey, arable farms are defined as farms growing combinable and/or potato crops. These farms may also grow other crop types and/or have livestock in addition to arable crops.

8) The term occurrence is used to describe the number of holdings on which a formulation has been used. Multiple uses of the same formulation at a holding are recorded as a single occurrence.

9) When collecting information regarding seasonal use of rodenticides, farmers and contractors were asked to report seasonal baiting patterns. The definition of season may vary among respondents. Where exact dates of use were provided these were assigned to season as follows: spring (March, April, May), summer (June, July, August), autumn (September, October, November) and winter (December, January, February).

10) Throughout the tables, data based on 10 or less sampled occurrences (rodenticide formulations encountered on 10 or less holdings) are highlighted and should be treated with caution as these estimates are likely to have a high associated error. In this survey only coumatetralyl, bromadiolone, difenacoum and brodifacoum were encountered on more than 10 holdings.

11) Data from the 2018^[1] and 2020^[2]surveys of rodenticide use on arable farms are provided for comparison with the estimates from arable farms in this survey. It should be noted that differences in use between years may be influenced by a number of factors such as rodent populations or the proportion of farms sampled in that year which had livestock or grain stores or were members of a quality assurance scheme in which rodenticide use was mandatory or encouraged.

12) Due to rounding, there may be slight differences in totals both within and between tables.

13) The June Agricultural Census is conducted annually by the Scottish Government's Rural and Environmental Science Analytical Services (RESAS). The June Agricultural Census collects data on land use, crop areas, livestock and the number of people working on agricultural holdings. In past reports the June census data was used to draw a sample of farms growing the relevant crops to participate in the survey, but for this report the May 2022 Single Application Form (SAF) data^[12] was used instead as the 2022 June census was paused (See Appendix 4 – changes from previous years for further information).

14) The UK Rodenticide Stewardship Scheme^[8] was implemented in April 2016 to reduce risks to wildlife and the environment from anticoagulant rodenticides. By mitigating these risks to the environment, the scheme aims to provide the Health and Safety Executive (HSE) with the confidence it requires to permit the continued authorisation of anticoagulant rodenticides for rodent pest management.