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

Executive summary

This report presents the results of a survey of rodenticide use on Scottish farms growing grass and fodder crops in 2021. Information was collected from 601 holdings, which collectively grew three per cent of the 2021 fodder and grass crop area. Data from this sample were used to estimate total Scottish rodenticide use in this crop sector.

It was estimated that rodenticides were used on 27 per cent of all grass and fodder farms in 2021, significantly fewer than in 2017 (35 per cent) and 2013 (43 per cent). Farmers conducted the baiting on 56 per cent of holdings using rodenticides and applied 58 per cent of rodenticides by weight, with the remainder being applied by pest control professionals (PCPs). This is significantly lower than in 2017, where farmers were responsible for baiting on 73 per cent of farms where rodenticides were used. In 2021, an estimated 85 tonnes of rodenticide products were used on grassland and fodder farms. This is a decrease of 34 per cent since 2017 and 61 per cent lower than in 2013. The products used contained ca. six kg of rodenticide active substance. As in previous surveys, almost all products used (>99 per cent) were second generation anticoagulant rodenticides, primarily bromadiolone and difenacoum (94 per cent by weight).

Sixty nine per cent of rodenticides were applied throughout the year, either used permanently or in multiple individual baiting operations. This is an increase in year-round use from 2017 (54 per cent) but lower than 2013 (75 per cent). Most rodenticides were used in Autumn and Winter (61 per cent). Grain baits were the most common product type (89 per cent) and the main targets were a combination of rats and mice (69 per cent). Forty seven per cent of farms that did not use rodenticides and 48 per cent of those that did, employed non-chemical rodent control; most commonly cats and traps.

Data were collected about training, compliance with best practice and aspects of farm operation. Fifty four per cent of farmers were aware of rodenticide stewardship. Overall, 17 per cent of farmers had completed stewardship compliant training and 21 per cent planned to in the future. As in previous surveys, significantly more PCPs had completed training than farmers. In relation to best practice, the majority of farmers and PCPs stated they complied with all elements and responses were similar to those in 2017. Whilst a higher proportion of PCPs reported compliance, the only difference was, there was some evidence that farmers were less likely to search for and remove rodent carcasses. In addition, PCPs were significantly more likely to use non-toxic indicator baits to monitor rodent activity than farmers. In relation to farm operation, farmers that practised rodenticide baiting were significantly more likely to be members of a quality assurance scheme and to have livestock and a grain store than farmers that did not use rodenticides.

Twenty per cent of the responding PCPs stated they had encountered or suspected resistance to rodenticides on farm. Sixty seven per cent of these PCPs stated they changed bait formulation due to this suspected resistance, 17 per cent switched to using traps and 17 per cent stated they suspected it was behavioural resistance only. Farmers were not asked about suspected resistance during this survey, but this data will be collected in future surveys.

This dataset is the second in this series to be conducted since the industry led stewardship scheme was introduced in 2015. This survey, and the previous survey in 2017, display a trend of decreased rodenticide usage, increased baiting by PCPs rather than farmers, and increased uptake of best practice which is likely to have been influenced by the introduction of stewardship and concurrent regulatory changes.