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Abstract

Mechanistic understanding of the spatio-temporal distribution of the grey field slug (Deroceras reticulatum) as part of the SLIMERS (Strategies Leading to Improved Management and Enhanced Resilience against Slugs) project.

Description

The grey field slug Deroceras reticulatum is one of the most damaging pest species in arable crops in the UK such as winter wheat and oilseed rape.

It feeds on seeds or emerging plants, causing significant damage including crop failure

Previous work at ÎåÒ»³Ô¹Ï×îйÙÍø has shown that in UK arable fields, grey field slugs are known to form higher density patches that are spatio-temporally stable throughout the cropping season.

Under normal environmental conditions patches form and remain stable because of changes to locomotory behaviour when slugs encounter conspecifics that result in localised movement. This behaviour may be reinforced by subsequent egg laying in batches which can lead to juvenile aggregation and by the need for slugs to huddle together to preserve body moisture.

Since 2022, ferric phosphate has been the only authorised conventional active ingredient for slug control in the UK, raising concerns relating to overreliance on a single substance.

Biological control agents such as nematode Phasmarhabditis hermaphrodita are available but currently not cost-effective in arable crops.

To maintain commercially viable control while reducing the amount of molluscicide applied, the potential for targeting products only at slug patches and leaving interpatch areas untreated is being investigated (would save up to 40–50% product, lowering the costs and environmental impact of pest control).

All previous field work in this research programme conducted under the normal soil moisture range encountered in arable fields; but very high soil moisture negatively affects slug survival and egg development.

Climate change results in increased severity/frequency of extreme weather events (e.g.  rainfall and flooding leading to waterlogging of fields). Its impact on slug patch formation and stability is unknown.