‘Slug sleuth’ farmers in England help develop prediction tool to cut back on pesticide use
English farmers, collaborating with scientists, have created prediction maps that help target slug infestations more precisely, reducing pesticide usage. The Slimers project has already allowed participants to halve their use of slug pellets.
Farmers in England believe they have a new weapon in their age-old battle against slugs: modern technology. Slug prediction maps, generated by computer models as part of a research project, are now helping growers to better target pesticide use, saving money and reducing environmental harm.
Slug damage is not just frustrating – it is also expensive for arable farmers. In the UK, damage to wheat and oilseed rape crops is estimated to cost almost £44m a year. These gastropod molluscs graze on young leaves of emerging cereal crops and also eat barley, oat and wheat seeds. They damage potatoes and can have a huge impact on vegetable crops, with whole fields sometimes abandoned due to infestation.
The monitoring work is carried out under the Slimers project (Strategies Leading to Improved Management and Enhanced Resilience to Slugs). This three-year, £2.6m scheme, which began in 2023 and ends in late August, is funded by the Department for Environment, Food and Rural Affairs and led by the British On-Farm Innovation Network.
A team of 28 “slug sleuth” farmers were recruited to work alongside scientists. They set up traps – large plastic saucers – on their land to understand slug behavior. The data was fed into a computer model, and an algorithm predicted where slugs would be found in arable fields, with soil samples also taken. The resulting prediction maps were tested by 16 farmers over the past autumn and winter, and have already helped them halve the amount of slug pellets needed.
Charles Paynter, a farmer in Bedfordshire involved from the start, has reduced pesticide use. “My threshold for taking control measures is higher now because I have been able to prove to myself that I can evaluate the risks from slug activity with greater accuracy,” he said.
The chemical metaldehyde, commonly used in slug control, was banned in the UK in 2022, leading to increased use of ferric phosphate pellets. However, there is appetite for alternatives to pesticides.
Prof Keith Walters and his team from Harper Adams University created the slug prediction model. “We already knew that slugs didn’t occur randomly across fields, but that they form distinct patches according to soil type and climatic conditions,” Walters said. “The slug sleuths’ data helped us develop that understanding further and confirmed our hypothesis about how slug patches re-form after waterlogging. In waterlogged soils, patches become unstable and break down, but we have now confirmed that patches re-form temporarily in places we wouldn’t expect in normal conditions and then quickly return to predicted areas once typical soil conditions return.”
Another part of the Slimers project involves developing slug-resistant wheat varieties. Scientists have identified three areas of the wheat genome responsible for resistance to the grey field slug, paving the way for plant breeders to develop new varieties not damaged by this persistent pest.
