Pesticide Usage in Scotland: Rodenticides on Grassland and Fodder Farms 2021

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 2021 survey period were: FGARs (coumatetralyl and warfarin), SGARs (brodifacoum, bromadiolone, difenacoum, difethialone and flocoumafen) and non-anticoagulant rodenticides (alphachloralose, aluminium phosphide, cholecalciferol and carbon dioxide). The rodenticides encountered in this survey were; alphachloralose, brodifacoum, bromadiolone, cholecalciferol, coumatetralyl, difenacoum, difethialone, flocoumafen and warfarin.

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, fodder farms are defined as farms growing crops for stock-feeding such as turnips, swede, kale, fodder rape, fodder beet, maize and arable silage (grain and legumes). Grassland farms primarily grow grass for grazing or silage. Fodder farms usually also have some grassland and grassland farms may also grow some fodder 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 bromadiolone, difenacoum and brodifacoum were encountered on more than 10 holdings.

11) Data from the 2013⁽¹⁾ and 2017⁽²⁾ surveys of rodenticide use on grassland and fodder farms are provided for comparison with the estimates 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, weather patterns, 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 effective rodent control was required.

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

13) The June Agricultural Census⁽¹¹⁾ 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. For this report the Census was used to draw a sample of farms growing the relevant crops to participate in the survey.

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.