Multispectral imaging for screening nematode-based biocontrol agents against slugs

Overview

Slugs are a significant agricultural pest, traditionally managed through chemical molluscicides such as metaldehyde and ferric phosphate. Biological control using nematodes offers a more sustainable alternative, but only one species (Phasmarhabditis hermaphrodita) has been successfully commercialised. Identifying additional nematode candidates is essential to reducing dependency on chemical controls.

This project investigates the use of multispectral imaging (MSI) as a screening tool for detecting nematode infection in slugs. Current identification methods rely on laborious field collection, dissection, and isolation, making the discovery of new biocontrol candidates slow and resource-intensive. Preliminary findings from CHAP's SlugBot project suggest that MSI can visualise internal slug body structures, potentially enabling early detection of infection and accelerating candidate discovery.

Technical specifications

Core technology: Multispectral imaging systems capable of capturing reflectance and spectral signatures across multiple wavelengths.

Key features:

• Imaging of internal slug body structures without dissection
• Detection of spectral variations associated with nematode infection over time
• Capability to operate under both laboratory and greenhouse conditions
• Comparison framework using the commercially available P. hermaphrodita strain as a benchmark
• Potential for future adaptation to entomopathogenic nematode species

Validation methodology:

• Field collection of pestiferous slugs and wild nematode strains in the UK
• Baseline MSI imaging of healthy slugs at CHAP's phenotyping lab
• Injection of nematode suspensions onto slugs followed by repeated imaging over a six-month period
• Analysis of reflectance and spectral signature changes linked to infection progression

Technology readiness level

This project is at an early-to-mid stage of feasibility validation. Preliminary results from the SlugBot project (Innovate UK: 106073) have demonstrated proof-of-concept for MSI-based imaging of slug internal structures. The proposed six-month study under laboratory and greenhouse conditions will establish whether MSI can reliably detect nematode infection signatures. Findings will contribute to larger grant bids aimed at developing autonomous biocontrol detection systems with broader applicability to entomopathogenic species.