Farmers help develop next-generation slug prediction tool

Farmers could soon be able to target slug control more precisely after a Defra-funded project developed maps predicting where the pest is most likely to strike.

The slug prediction tool has been developed through SLIMERS, a three-year research programme led by the British On-Farm Innovation Network.

The project, which stands for Strategies Leading to Improved Management and Enhanced Resilience to Slugs, has brought together farmers, agronomists and researchers to improve slug control in arable crops.

A team of 28 Slug Sleuth farmers and agronomists collected field data to help researchers better understand slug behaviour.

The work enabled Prof Keith Walters and his team at Harper Adams University to develop and validate a model predicting where slugs are most likely to be found in arable fields.

Soil sampling across the monitoring sites by Agrivation also formed part of the analysis.

The maps could allow growers to target control measures more precisely, reducing blanket slug pellet applications while improving crop protection.

Prof Walters said researchers already knew slugs did not appear randomly across fields.

“Coming into SLIMERS we already knew that slugs didn’t occur randomly across fields, but that they form distinct patches according to soil type and climatic conditions,” he said.

“The Slug Sleuth’s data of slug populations across their fields helped us develop that understanding further and allowed us to confirm our hypothesis about how slug patches re-form after waterlogging.”

The project has also improved understanding of how slug patches behave after prolonged wet conditions.

Prof Walters said waterlogged soils could cause patches to become unstable before they returned to predicted areas once more typical conditions resumed.

That understanding helped strengthen a model designed to explain the biology behind patch formation and support forecasting of future slug risk.

The resulting slug prediction maps were tested by Slug Sleuth farmers during autumn and winter 2025-26.

Although slug numbers were low during the testing period, Prof Walters said the project had still produced enough data to show the model worked.

“Despite low slug numbers over the testing period we have sufficient data to prove that the model works,” he said.

“And perhaps most importantly, that farmers are happy to use it and it fits in with modern commercial equipment.”

He said the farmer-scientist partnership had been central to the project.

“I have no doubt our farmers collected data to the same level of accuracy as trained technicians,” he said.

Prof Walters said involving farmers from the start had made the work more relevant to commercial conditions.

“Farmers brought a different perspective and expertise,” he said.

“That knowledge is vital and you don’t get it unless the farmers involved have some level of ownership in the research and its outcomes.”

Bedfordshire farmer Charles Paynter, who was involved in the project from the beginning, said the findings could help growers treat slug problems more accurately.

“With the findings from SLIMERS research, together with new technical developments, we can predict slugs’ activity more accurately than before,” he said.

“This means we will be able to use more targeted treatments which has the potential to be less damaging to biodiversity.”

Mr Paynter said the project had already changed his approach to slug control.

He has reduced the amount of slug pellets applied to his crops and said his threshold for taking action was now higher.

“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.”

Nottinghamshire farm manager Richard Cross said he had also moved away from blanket applications of slug pellets since joining the project in its first year.

“I’ve learned that slug issues can be controlled in a more environmentally friendly way,” he said.

However, he said further work was needed before the findings could be fully rolled out on farm.

“I don’t think this project is concluded yet - we need funding to get the variable rate applications out on farm to build up a data set to prove the theory.”

SLIMERS is a £2.6 million research programme involving more than 100 farms and seven partners, and is due to conclude in August 2026.

It is funded through Defra’s Farming Innovation Programme and delivered by Innovate UK, with partners including the UK Agri-Tech Centre, Harper Adams University and the John Innes Centre.

Alongside slug prediction and precision mapping, the consortium has also been developing an AI-based autonomous system for targeted biological control and exploring slug-resistant wheat varieties.

With slug damage estimated to cost £43.5 million a year, the project’s backers say more precise prediction and treatment could help growers reduce losses while limiting unnecessary applications.