Efficacy of chemical and biological slug control measures in response to watering and earthworms

Daniel Dörler,Johann G Zaller,Agnes Scheucher

doi:10.1038/s41598-019-39585-5

Daniel Dörler, Johann G Zaller + Show 1 more

Open Access

https://doi.org/10.1038/s41598-019-39585-5

Copy DOI

Abstract

The Spanish Slug (Arion vulgaris, formerly known as Arion lusitanicus) is an invasive agricultural and horticultural pest species that causes great damages all over Europe. Numerous options to control this slug are on the market; among the most commonly used are slug pellets containing the active ingredients metaldehyde or iron-III-phosphate and the application of parasitic nematodes (Phasmarhabditis hermaphrodita). These control measures potentially also affect non-target organisms like earthworms (Lumbricidae), which themselves can directly and/or indirectly alter a plant’s susceptibility against slug herbivory. Also, the efficacy of slug control treatments is expected to be influenced by watering. In a greenhouse experiment we investigated the influence of daily watering vs. every third day watering on slug control efficacy and potential interactions with earthworms. We found significant interactions between watering and slug control efficacy. Slug herbivory and biomass decreased after application of slug pellets; metaldehyde was more effective under less frequent watering while iron-III-phosphate was unaffected by watering. Parasitic nematodes had no effect on slug herbivory and biomass production. Earthworm activity was reduced with less frequent watering but did not interact with slug control. We conclude that watering patterns should be considered when choosing slug control measures.

Highlights

Whereas the majority of snail and slug species are not pestiferous, some are causing great damages in agriculture, horticulture and private gardens[1,2,3,4,5,6,7,8]
Slug herbivory and slug weight were significantly influenced by slug control but unaffected by the watering regime, earthworms or their interactions (Table 3)
Iron-III-phosphate (p < 0.001) and metaldehyde (p < 0.001) influenced slug weight significantly compared to the nematode treatment and the control group, which did not differ from each other

Summary

Introduction

Whereas the majority of snail and slug species are not pestiferous, some are causing great damages in agriculture, horticulture and private gardens[1,2,3,4,5,6,7,8]. Less often used are biological control measures with the parasitic nematodes Phasmarhabditis hermaphrodita[39,40,41,42,43,44,45]. The effectiveness of these slug control measures can be altered by biotic factors such as the size of the slugs[46] or a slugs’ interaction with other organisms living in the same habitat. Earthworms, for example, have been shown to reduce the efficacy of slug control by consuming slug pellets[47]. The objective of this study was to test the effectiveness of different slug control methods under different irrigation regimes or their interaction with earthworms, as well as potential interactions between irrigation www.nature.com/scientificreports/

Objectives

Methods

Results

Conclusion