Pesticide usage in Scotland: Grassland and Fodder Crops 2021

Executive summary

This report presents information from a survey of pesticide use on grassland and fodder crops in Scotland in 2021. The crops surveyed included direct sown grass, undersown grass, grass one to four years old, grass over five years old, rough grazing, arable silage, fodder beet, fodder rape, kale and cabbage, maize, stubble turnips, turnips and swedes and other minor fodder crops. Information about the uptake of integrated pest management measures by Scottish growers (including non-chemical methods of control) was collected alongside the pesticide usage survey.

The estimated area of grassland and rough grazing grown in Scotland in 2021 was approximately 4,403,000 hectares, similar to that grown in 2017. Rough grazing accounted for 70 per cent of the total area grown, grass over five years 26 per cent, and grass under five years four per cent.

The fodder crop area was approximately 17,200 hectares, a six per cent increase from the previous survey in 2017. Other stock-feeding crops accounted for 38 per cent of fodder crops grown, of which 84 per cent was arable silage. Turnips and swedes accounted for 20 per cent, fodder rape 13 per cent, kale and cabbage 12 per cent, maize seven per cent, fodder beet seven per cent and stubble turnips three per cent.

Data were collected from 182 holdings with both fodder crops and grassland, and an additional 438 holdings with grassland only. This sample represented 16 per cent of total fodder crops grown in Scotland, six per cent of grassland area and two per cent of rough grazing. Ratio raising was used to produce estimates of national pesticide use from the sampled data.

The estimated total area of grassland and rough grazing treated with a pesticide formulation was ca. 81,000 ha (± 11 per cent Relative Standard Error, RSE), with a combined weight of 67 tonnes (± 11 per cent RSE). Overall, these pesticides, almost exclusively herbicides, were applied to four per cent of grassland and less than 0.5 per cent of the rough grazing area. Taking into account changes in crop area, the 2021 total pesticide treated area on grassland and rough grazing was nine per cent lower than that reported in 2017 and seven per cent lower than in 2013. The weight of pesticide applied was 21 per cent lower than in 2017 and 22 per cent lower than 2013. The decrease in overall pesticide use in 2021 from 2017 and 2013 may have been influenced by a number of factors. A cold, dry spring in 2021 may have reduced pest pressure and thus the need for pesticide use. The estimated reduction in herbicide use was also influenced by the infrequency of aerial spraying encountered in the 2021 sample. Additionally, the continued reduction in pesticide options may also have influenced use figures, with several of the key active substances used during 2013 and 2017 now being withdrawn and were unavailable in 2021.

The estimated total area of fodder crops treated with a pesticide formulation was ca. 25,100 ha (± eight per cent RSE), with a combined weight of ca. 10 tonnes (± 12 per cent RSE). Pesticides, primarily herbicides, were applied to 38 per cent of fodder crops. When changes in crop area is accounted for, there was a decrease of two per cent in total area treated with pesticide formulations from 2017 to 2021 and a 32 per cent decrease from 2013. Weight of pesticide applied showed a 20 per cent increase from 2017 and a 21 per cent decrease from 2013. The application of insecticides, fungicides and herbicides increased in terms of weight applied (230, 142, and 13 per cent respectively), whilst the application of seed treatments and molluscicides decreased (42 and 44 per cent respectively).

The decrease in area treated but the increase in weight applied between 2017 and 2021 may have been influenced by the loss of seed treatment active substances (thiram and thiamethoxam) and the subsequent increase in foliar fungicides and insecticides. In addition, pesticide usage was low in 2017, influenced by the particularly dry spring, drier than 2021, so pest pressure was particularly low.

In terms of area treated, the most commonly used herbicide on grassland and fodder crops was fluroxypyr and the most used foliar fungicide and seed treatment was prothioconazole. The pyrethroid deltamethrin was the most commonly used insecticide. The herbicides halauxifen-methyl, mesosulfuron-methyl and napropamide, the fungicides benzovindiflupyr and mefentrifluconazole, the seed treatments sedaxane and ziram, and the insecticide flonicamid were recorded for the first time in this survey.

Data collected from growers about their Integrated Pest Management (IPM) activities showed that growers were using a variety of IPM methods in relation to risk management, pest monitoring and pest control. This dataset is the second in this series of surveys of IPM measures on grassland and fodder crops, allowing the adoption of IPM techniques to be monitored. There was very strong evidence for an increase in the use of IPM plans from the 2017 survey (24 per cent in 2021 compared to five per cent in 2017).