Terrestrial slugs have colonised all continents, and are important economic pests of a number of crop types, including arable, pasture, ornamental and vegetable crops. Their ability to have both sex organs, produce hundreds of eggs and breed at any time of the year, show their status as ‘super pests’. They attack plants by destroying their stems and growing points, target seedlings and seeds, and reduce the leaf area. In some cases, the damage that is done to germinating seeds is so severe that entire fields must be resown, resulting in huge economic losses to farmers.
In addition to crop pests, many slug species act as intermediate hosts for parasites, making them a potential human health risk, as well as a risk to livestock and wildlife.
Current methods for controlling these pests rely heavily on chemical molluscicides, such as metaldehyde and iron phosphate. Previously carbamate compounds were also used, however these have now been removed from the European market due to their toxic impact on non-target organisms. Metaldehyde is also under scrutiny after high levels were recorded in water systems across Europe, so usage is now tightly controlled. Other control options that are available to farmers include biological and cultural control, however these are often expensive and/or unrealistic for large scale agriculture. Therefore, the future of slug control is uncertain, and this is especially true for the UK, where global warming will see the country getting wetter and warmer, making it an ideal breeding ground for both indigenous and European invasive slug species.
One major concern is the biological invasion of the Spanish slug, Arion vulgaris, into the UK. Arion vulgaris has the ability to mate with our local black slug, the Arion ater, to produce super-hybrids, that can survive both hot and cold temperatures, produce increased offspring, and have high levels of resistance to chemical pesticides. It is predicted that the successful invasion of this species into the UK will have a major impact on UK agriculture.
Therefore, the aim of this project is to collate global information on slug control, in order to enhance farming methods in the UK. Objectives of this study include:
- 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
The project will involve liaising with farmers and researchers in Europe, USA, Canada, Australia, New Zealand, Brazil, South Africa and Kenya, to gather global data, which can then be developed as a working document for UK farmers.