Final Report – ‘Riding the Slime Wave’

I am absolutely delighted to announce that my Nuffield Farming report entitled ‘Riding the Slime Wave: Gathering Global Data on Slug Control’ has been published. After 8 months in the Nuffield editing hot seat, it has finally made it through to the other side and is now available for download here.

My Nuffield journey started back in 2017 after reading the newspaper headline ‘500 BILLION slugs set to invade Britain after springtime sex frenzy swells the population by 20% – The fine weather has caused a slug orgy and now gardeners will have to pay a steep price for the beasties’ slimy lust’.

Now as a self-proclaimed slug detective, this more that caught my attention….so much so that I decided to make it my mission to apply for a Nuffield Farming Scholarship to get to grips with these slimy creatures. Two years on, and 26 weeks of international travel later, I am proud to deliver this report and hope that its outputs will help UK farmers and avid gardeners assess their current control strategies, as well as highlight the importance of having robust biosecurity protocols in place in order to prevent future biological invasions of exotic slugs into the UK.

Acknowledgments:

I would like to take this opportunity to thank my husband and my family for their continual support during my Nuffield travels. Without their encouragement this wouldn’t have been possible. I would also like to record my thanks to the staff at the Nuffield Farming Scholarship Trust, including Christine Hill for editing my report, and to my main sponsors, the Royal Highland and Agricultural Society of Scotland, and the Agricultural and Horticultural Development Board Cereals and Oilseeds, for their support. Special thanks to Alan Laidlaw and Martin Grantley-Smith for their mentorship during the process.

In addition, I would also like to thank Jan Redpath for his friendship and mentorship throughout my Nuffield journey.

I would also like to thank the Mains of Loirston Charitable Trust for their significant contribution towards my project, as well as the Council for Awards of Royal Agricultural Societies (CARAS), LANTRA, Robert Nicol Trust, MacRobert Trust, Rotary Club of Aboyne and Upper Deeside, Royal Northern Agricultural Society, W.N Lindsay Ltd, Lonza Group, North East of Scotland Farm Management Association, Scottish Agronomy and Aberdeen and Northern Marts.

Also, my thanks to all the contributors to this study, without which this report wouldn’t have been possible. And finally, thanks to all the slugs that made this possible!

Summary of Report

Background:

Slugs are important economic pests worldwide, targeting an array of agricultural and horticultural crops. Current methods for controlling slugs in the UK rely heavily on the application of chemical molluscicide pellets, containing either metaldehyde or Iron (Ferric) phosphate. However, in December 2018, the Department for Environment, Food and Rural Affairs (Defra) made the decision to ban the outdoor use of metaldehyde due to its impact on birds and mammals.  Conversely, in July 2019, the High Court overturned the ban, ruling that the decision-making process by former Defra Secretary, Michael Gove, was unlawful, leaving the future of chemical slug control up in the air.

In addition to the controversy over chemical molluscicides, there are also concerns over biological invasions, especially relating of the Spanish slug, A. vulgaris, which has established as a major agricultural pest across much of Europe. However, little is known about the impact and extent of the distribution of this slug species in the UK, as well as other potential slug invasions.

Finally, with a huge amount of money invested in controlling slugs in the UK, perhaps there is an opportunity being missed to utilise these animals, and their bi-products, as a commercial venture.

Objectives:

• Characterise the key slug species in the UK
• Identify potential slug invasions and their impact on biosecurity
• Determine direct and indirect economic risk of slugs
• Review slug monitoring systems
• Evaluate slug control options
• Determine the future of malacology
• Investigate novel commercial opportunities for the utilisation of slugs

Conclusions:

• Over 50% of slug species in the UK are exotic, so it is imperative that biosecurity protocols are developed to prevent further slug invasions;
• Slugs have a direct economic impact on crop damage, as well as an indirect impact on human and animal health, rejection of exported crops due to contamination and impact on soil health (through slug control strategies);
• There is a drive to incorporate technology into slug monitoring systems;
• With uncertainty over metaldehyde, Iron (Ferric) phosphate may be the only ‘chemical’ control option available in the future;
• The use of nematode bio-molluscicides is currently not feasible in broadacre crops due to cost, volume of water required, storage and shelf life;
• Agronomic and cultural practices are playing an increasing role in controlling slugs, with a surge in farmer led research in this area;
• Farmers should consider a slug IPM strategy pyramid, tailor-made to each field;
• The study of malacology appears to be in difficulty, with no clear succession plan in place, and limited funding to share and develop ideas; and
• Perhaps we are missing an opportunity and we should be farming slugs instead, targeting slugs and their bi-products towards the food, cosmetic and pharmaceutical industries.

Recommendations:

National Strategic Action:

• Conduct a systematic survey to better understand the slug fauna of the UK;
• Implement biosecurity protocols to prevent future biological invasions of exotic slugs into the UK;
• Employ an eradication protocol for the Spanish slug, A. vulgaris; and
• Make changes to regulatory system to speed up registration process for new molluscicide products.

Industry and Research Action:

• Calculate the monetary value of direct and indirect impact of slugs;
• Develop real-time mobile monitoring and treatment systems for slugs;
• Investment into the development of new and current chemical, biorational, physical barriers and biological control methods;
• Develop a system to deliver a slug IPM strategy pyramid that is tailored to each field;
• Scientists should work alongside farmer groups to translate scientific findings into practical outputs; and
• Investigate opportunities for farming slugs for the food, cosmetic and pharmaceutical industries.

Malacology Knowledge Exchange Action:

• Re-establish conference opportunities, such as the BCPC Slug and Snail meetings, and secure funding to continue the IOBC Slug and Snail conference, in order to share and develop ideas;
• Promote malacology to the next generation, and prepare succession plans to avoid the loss of key knowledge; and
• Encourage citizen science programmes in malacology to engage and educate local communities on slugs, damage and methods of control.