Category: SLIMERS+

Since stepping back from full-time management of his Bedfordshire farm, Charles Paynter has thrown himself into on-farm trials, keen to keep innovating and sharing his learning with other farmers.

As a Slug Sleuth, Charles has taken a hands-on role in monitoring slugs on his farm but he’s also trialling wheat varieties flagged by researchers as potentially more resistant to slug damage. He’s kept a close eye on how these varieties establish and withstand pressure, sharing his findings with researchers and other farmers along the way.

Meticulous record-keeping is central to Charles’s approach: “I record my observations in the field and keep records of every chemical input too.” This detailed approach not only helps him track what’s working on the farm, but also builds a knowledge base that benefits the wider farming community.

The appeal of on-farm trials is simple, he says. “There’s no substitute for seeing how something performs in your own fields.” He values the opportunity to test new ideas in real farm conditions and adapt them based on first-hand results. He’s found that being part of the wider BOFIN network of farmers and researchers is a huge benefit too. Sharing experiences – both successes and failures – means everyone moves forward faster. “Every farmer has something to share, and you learn something from them all,” he says.

His involvement in SLIMERS is particularly timely as the move to regenerative practices at Rifle Range Farm, while positive for soil health, often means more crop debris and higher slug pressure. That makes it even more important to find targeted, sustainable ways to manage slugs without relying on blanket chemical applications, he says.

Charles is clear that farmers need to be at the heart of projects like SLIMERS. “All roads come back to the farmer. As individuals we may not be the most technical, savvy or proficient, but we have farmer experience and instinct, and no amount of research can replace that.”

Rifle Range Farm:

• 221ha
• Winter wheat, spring wheat
  and peas
• Regenerative approach
• Deep, non-inversion cultivations
• Heavy soil (chalky boulder clay

Pearson Gape Farming Partnership (Cambs)

At Manor Farm, Caxton, farm manager Rhys Jones is tackling the pervasive problem of slugs head-on through involvement in SLIMERS. For farm owner Tom Pearson, embracing regenerative agriculture meant finding alternatives to conventional, more input-heavy, farming practices. This included introducing cover and companion crops, leaving chopped straw on the field before direct drilling, as well as a no-till controlled traffic policy. These practices although beneficial in many other ways, have an impact on slug control.

Rhys explains: “The brassicas in our cover crop mix and fields with chopped straw are slug havens, so joining the project was another opportunity to reduce inputs.”

Through monitoring slug populations using simple traps and meticulously recording data throughout the winter months Rhys has been contributing to the SLIMERS project’s broader goal of understanding slug behaviour and developing more targeted control strategies.

He’s enjoyed the process and learned a lot about managing trials along the way. Beyond monitoring, Rhys is also trialling a variety of ‘slug resistant’ wheat. He is growing the Watkins variety and two RILs alongside his farm standard ‘Nelson’ to see whether the variety is indeed rejected by slugs.

The data collected by Rhys and other ‘Slug Sleuths’ is being used to refine control methods, potentially leading to the development of patch treatments, AI-powered monitoring systems, and automated slug control technologies.

The emphasis on farmer involvement and practical solutions is a key strength of the SLIMERS project, says Tom Pearson. “What BOFIN brings to the party is they are delivering proper research outcomes, but are very farmer orientated and asking questions that are relevant to farmers.”

For Manor Farm, participation in the SLIMERS project is about more than just controlling slugs. It’s about contributing to a wider movement towards sustainable agriculture, reducing reliance on chemical inputs, and fostering a deeper understanding of the complex ecosystems within our fields. It is also interesting for farm staff to be involved in this type of work, as Tom mentions: “It’s good to be part of something that is helping the industry while also contributing to making my farm a more exciting workplace.”

Agrivation, led by precision farming specialist and farmer Clive Blacker, plays a crucial role in the SLIMERS project by providing high-resolution soil mapping and sampling for the Slug Sleuths’ fields. This vital baseline data supports the project’s efforts to better understand the relationship between soil conditions and slug activity.

Clive uses advanced precision agriculture tools, including electromagnetic induction (EMI) scanning, RTK GPS-referenced soil sampling, and drone imagery, to create detailed maps of soil texture, variability, and moisture holding capacity. These maps help to identify potential slug hotspots that guide trial layout for both monitoring and management strategies, and provide the baseline for variable rate applications.

Each year, shortly after harvest, Clive visits each Slug Sleuth farm to carry out the initial soil mapping. Following drilling, he returns to establish a dedicated 1-hectare monitoring plot. This plot is overlaid with a georeferenced 10×10 grid and fitted with 100 slug refuge traps. Care is taken to align the grid with areas known to be slug-prone based on both farmer insight and soil characteristics revealed through the mapping.

As the project progresses, the data provided by Agrivation is being used by researchers at Harper Adams University to support the development of the slug patch prediction models. These models aim to help farmers target slug control more effectively, reducing pesticide use while protecting crop establishment.

Clive says: “Working alongside the Slug Sleuths on this project has been a fantastic opportunity to combine cutting-edge soil science with practical, on-farm decision making. By mapping the invisible – what’s happening beneath the surface – we’re helping build the evidence base that will lead to smarter, more sustainable slug control.”

Another exciting technological development within the SLIMERS project is the BOFIN trialist app.

Tom Allen-Stevens explains: “Monitoring and recording so many data points within the project has been a challenge. We have been using the HUSK app for the past two seasons, but this has its limitations.”

The new app, in beta-testing over summer 2025, has been developed so that all the Slug Sleuths carry out the monitoring work in a consistent way, for scientific validation. But feedback from the field has ensured data entry is practical and quick, giving users easy reference on progress of monitoring work.

The app has been designed so that it can be easily adapted to other on-farm trials, and will integrate with a novel wheat plant population tool, that will monitor wheat emergence using photos taken of the crop. Developed by Insight ML, the AI tool is being trained on around 3000 images of emerging crops taken by the Slug Sleuths.

“It’s been a job for us to find a consistent and objective way to monitor crop emergence and early growth. Last autumn, at each visit we all took photos of 20 quadrats marked out in the 1ha monitoring area. This year, we will hopefully be able to use the tool to tell instantly what the plant population is, which will be useful when monitoring all crops, not just within trials,” notes Tom.

Fotenix helps farmers grow sustainably and profitably with the power of AI. Its plug-and-play smart cameras help growers with quality control, targeting input use, and early detection of pests and disease.

Within SLIMERS Fotenix is working to identify slugs and create smart maps to guide targeted use of new, more sustainable pesticides.

CEO Charles Veys explains: “Our role is to build AI-powered slug detection, right there in the field. But first, we’ve got to train the AI, and that means putting slugs in the crosshairs.”

In early 2025 the team at UK Agri-Tech Centre scanned slugs across the Slug Sleuths’ farms, helping pinpoint the exact spectral signature of the
unwelcome visitors.

“This labelling approach is helping us to build libraries of key pests to allow development of software pipelines that can spot slugs earlier, and more accurately than a human or drone scout – a hot topic in pest management across crops.”

The next step is to scale the tech from trials to commercial scale, and integration with Farmscan Ag’s automated sprayer to move one step closer to viable per-slug detection and treatment.

The result in sight is smarter slug control, reduced chemical use, and stronger crops

Developing a highly targeted spray system is the task for the team at Farmscan Ag. The company, which was founded in Australia, now works with manufacturers of agricultural equipment across the UK too. Its aim is to support precision farming and crop management, developing high-efficiency tools including autonomous farming, crop sprayer technology and liquid fertiliser application.

“While the researchers are working on predicting where slugs will be and identifying them in situ, we are the application partner – converting that knowledge into real world activity,” explains director Callum Chalmers.

“The end goal is an automated system that will find slugs in the field and spray them precisely with nematodes. These are very expensive so unless application is highly accurate it won’t be viable.”

The team is working on making spray width as small as possible and once developed the spray system will be added to an existing autonomous farm vehicle. “We are aiming for 25cm or less, which would mean four nozzles per metre,” explains Callum. “We are running first trials at the end of 2025, then field trials will be in full swing in early 2026.

“It’s great to be part of the SLIMERS project. I believe the government will continue to clamp down on agrichemicals, so farmers need economically viable alternatives.”

As Research Associate at the UK Agri-Tech Centre and a core member of the SLIMERS project, Dr Kerry McDonald-Howard is combining expertise in sustainable pest control with advanced digital tools to transform how farmers manage slugs.

While studying at Liverpool John Moores University, Kerry’s PhD focused on improving the efficacy of parasitic nematodes, specifically Phasmarhabditis hermaphrodita, as a biological control for slugs.

These nematodes, which are natural predators of slugs, thrive in the same moist, organic-rich soils favoured by slugs. Like slugs they also thrive in soils with higher organic matter and clay content, and at lower temperatures.

Nematodes, often called roundworms, are among the most abundant animals on earth. While most are harmless, a select few, like those in the Phasmarhabditis genus, are specialised slug parasites. These microscopic hunters track slugs by following their slime trails, enter through a small breathing hole, and ultimately kill their host within a few weeks. As they are harmless to other wildlife and the environment, they are considered a sustainable biological alternative to chemical molluscicides.

The key to effective nematode use is precision explains Kerry: “Nematodes can’t travel far in the soil, and applying them across an entire field would be prohibitively expensive. But if we can pinpoint exactly where the slugs are, we can target applications, making biological control both affordable and effective.”

Kerry works from the UK Agri-Tech Centre’s Phenotyping laboratory based at Rothamsted Research where they lead experiments using advanced imaging and AI to distinguish slugs. These technologies are being trained using thousands of images and data points collected by the project’s Slug Sleuth farmers and partners.

“Together with Fotenix we are building AI models that will recognise slugs, monitor populations, and apply nematodes precisely where they’re needed.”

So far, the SLIMERS team has successfully trained AI models to distinguish slugs from soil, plants, and stones and Kerry has more recently been working in Slug Sleuth’s fields, collecting more data, and refining both the technology and the biological control strategies.

This has involved taking the highly specialised Fotenix multi-spectral imaging equipment out into fields to collect more images of slugs
in a variety of locations. As slugs generally reach a period of peak activity on the soil surface starting two to three hours after dark Kerry has been heading out into the farmers’ fields late at night.

“With it being so dry it has been a challenge to find slugs this spring so we have had to wait until late when there is more moisture.”

Kerry is optimistic about the project’s impact. “The agricultural industry is in a constant struggle of needing to produce more with less, especially chemical inputs – not only because of the detrimental impacts to the environment and non-target organisms, but also the rising costs.
“The ability to monitor and control a massive pest of UK agriculture, in a sustainable and cost-effective manner is fundamental therefore, this project delivers economic, environmental and societal benefits.

Researchers at the John Innes Centre have been making progress towards identifying what makes some wheat varieties more ‘slug resistant’ than others.

This work is based on previous research that screened varieties from the centre’s Watkins collection of landrace wheat varieties. This singled out Watkins 788 as a potential front runner for ‘slug resistant’ properties after 78% of slugs demonstrated a dislike to it.

From there, the team at JIC, led by Dr Simon Griffiths, crossed Watkins 788 with commercial variety Paragon, to create 85 Recombinant Inbred Lines (RILs) for further testing.

Quantitative Trait Locus (QTL) analysis is a genetic tool that helps identify specific regions of a plant’s DNA linked to desirable traits, such as slug resistance in wheat. By combining data from field trials with lab-based genetic testing, researchers are getting closer to identifying which part of the genome influences the apparent resistance.

Researchers use DNA markers to scan the genomes of resistant and susceptible RILs. Regions consistently linked to lower slug damage are flagged. Once the QTLs are confirmed, those genetic markers can potentially be used to create new slug resistant varieties.

The centre’s Head of Entomology and Insectory Dr Victor Soria-Carrasco has run trials on these RILS using slugs that have been posted in by ‘Slug Scouts’. These are members of the public (including farmers) who collect and post containers of grey field slugs to the centre.

Dr Simon Griffiths, Group Leader and ‘Delivering Sustainable Wheat’ Programme Lead says: “Early results have highlighted a number of RILs that appear to be slug resistant, as well as those that are susceptible. Using the diverse wheat in our historic Watkins collection in these trials is really exciting, as we’re starting to see it becoming an increasingly useful resource for tackling the challenges that farmers face in the field.”

Two of these RILs as well as Watkins 788 were multiplied up for testing by six Slug Sleuth farmers who took on the additional responsibility within the SLIMERS project. The farmers established blocks of Watkins 788 and the two RILS – one believed to be resistant and the other susceptible to slugs – alongside their farm standard wheat. Over the 2024-5 growing year they have taken measurements and samples to find out if these are indeed spurned by slugs and could offer potential solutions to farmers.

Meanwhile the on-going lab-based feeding trials have identified other even more resistant RILs that are currently being multiplied up at the John Innes Centre field station near Norwich, and will be put into field trials in autumn 2025.

Research led by Professor Keith Walters is transforming understanding and management of slugs.

One of the key insights driving the SLIMERS project is that slugs don’t spread evenly across fields. Instead, they gather in patches hotspots with high slug numbers.

Previous research led by Keith established that these patches are not only common, but also stable throughout the cropping season, making them potential targets for selective control.

But there was still a lot to learn about the specific factors that caused slugs to form patches where they do, and how those locations can be reliably predicted.

Over the past two years, Slug Sleuths have been counting slugs, and recording data across 1ha plots on their farm. Their efforts, combined with detailed soil mapping and testing by project partner Agrivation and subcontractor Hutchinsons, have created comprehensive datasets on slug distribution.

This enabled Keith and his team to dig deeper into the factors influencing slug patch formation.

They found that soil characteristics including pH, organic matter, and the proportions of sand, silt, and clay all play a role in where slugs settle and breed thus forming patches. For example, slugs tend to avoid areas with higher pH or low organic matter, while clay-rich soils, which retain moisture, are particularly attractive to them.

The large datasets collected have allowed quantification of their varying impact on different aspects of patch formation at a level of detail never before achieved.

The first two years of the SLIMERS project coincided with unusually high rainfall, which gave the opportunity to study how slugs respond to waterlogged soils. The researchers discovered that when fields are saturated, slugs abandon their usual patch forming behaviour in favour of survival, dispersing more randomly. As soils dry out, patch formation resumes but often in the sandier, better-drained parts of the field first.

Predictive models for precision control

Armed with this new understanding, Keiths’ team has developed a suite of mathematical and AI-driven models:

•  A biological model that explains how slugs respond to different soil characteristics under both normal and waterlogged conditions.

•  A binary predictive model that identifies areas likely to exceed a threshold slug count (such as the AHDB’s four slugs per trap), helping farmers know where to focus control efforts.

•  An abundance model that aims to predict the level of surface activity of slugs in each part of a field. This is a more complex task, but one that’s showing promise as more data becomes available.

Initial tests of these models have been encouraging with the binary model, for example, already achieving nearly 80% precision when it predicts locations of high-risk patches. As more data is collected in the upcoming autumn trials, accuracy is expected to improve even further.

Saving money and protecting the environment

The implications for farmers are significant. By targeting slug control measures – whether using conventional pellets or biological alternatives like nematodes – only where they’re needed, growers can reduce input use and limit environmental impacts.

This approach not only makes economic sense, but also supports the industry’s drive toward more sustainable farming practices.

The next phase of the SLIMERS project (2025-26) will see these predictive models put to the test in real- world conditions. Slug Sleuths will receive detailed risk maps for their fields and be asked to treat only the predicted slug hotspots.

The results will help fine-tune the models and bring the vision of precision pest management closer to reality.