Pesticide Usage in Scotland: Arable crops and Potato stores 2022

Pesticide Usage in Scotland : Potato Stores 2022

Executive summary

This report presents information from a survey of pesticide use on stored potatoes harvested in Scotland in 2022. Data were collected from 73 growers, who collectively cultivated 28 per cent of the area of potatoes grown in Scotland. Pesticide use in potato stores was recorded for crops grown for seed production and for consumption (ware potatoes). Ratio raising was used to produce estimates of national pesticide usage from the sample data.

The overall estimated quantity of potatoes stored in Scotland in 2022 was ca 951,000 tonnes, a slight decrease of four per cent compared with the previous survey in 2020 and a nine per cent increase compared with 2018. Seed potato storage decreased by an estimated 15 per cent to ca. 332,700 tonnes. Ware potato storage increased by an estimated four percent to ca. 618,400 tonnes. However, there has been a significant change in survey estimation methodology which must be taken into account when comparing storage data from this survey and previous surveys.

Seventy eight per cent of seed and 82 per cent of ware potatoes sampled in 2022 were stored in refrigerated stores. The majority of the remaining stores were ambient ventilated stores. All the potatoes surveyed were stored in boxes.

The proportion of seed potatoes treated with a pesticide in 2022 was 25 per cent. This is lower than the 39 per cent treated in 2020 but similar to the proportion treated in 2018 (28 per cent). The proportion of stored ware potatoes treated with a pesticide in 2022 was eight per cent, similar to the six per cent treated in 2020, but lower than the 13 per cent treated in 2018.

The only pesticide encountered on seed potatoes was the fungicide imazalil, applied to an estimated 25 per cent of the stored crop for control of a range of tuber diseases. Imazalil was also the principal pesticide encountered in 2020.

As in 2020, the principal pesticide used on ware potatoes in 2022 was the growth regulator ethylene applied to an estimated four per cent of the stored ware crop, compared with four percent in 2020 and eight per cent in 2018. The sprout suppressant spearmint oil was applied to an estimated three per cent of the stored ware potato crop in 2022, similar to the one and two per cent treated in 2020 and 2018 respectively. Another sprout suppressant, 1,4-dimethylnaphthalene was applied to an estimated one per cent. This new active substance was only approved for use in potato stores from August 2022. Chlorpropham (which was withdrawn in 2020) had been the principal active substance in 2018 and 2016 (applied to nine and ten per cent respectively). Less than 0.5 per cent of the stored crop was treated with a fungicide in 2020.