Using the Copse snail Arianta arbustorum (Linnaeus) to Detect Repellent Compounds and theQuality ofwoodVinegar

Document Type: Original Research Paper

Authors

1 UniversityofHelsinki,Department ofEnvironmental Sciences,Niemenkatu 73, 15140 Lahti, Finland

2 VTTTechnical Research Centre of Finland, P.O. Box 1000, 02044VTT, Espoo, Finland

3 MTTAgrifood Research Finland, 31600 Jokioinen, Finland

Abstract

Wood vinegar is the aqueous phase of the liquid produced during the slow pyrolysis of wood.
It has the potential to be used as a pesticide against various weeds, insects and molluscs. Due to divergent
feedstocks, pyrolysis processes and storing conditions, the chemical composition of wood vinegar varies
between producers and time. The aim of our current study was to use the copse snail Arianta arbustorum as
a biological odour detector to identify the effective compounds behind the repellent effect of wood vinegar. We
also studied whether variation in the chemical composition of wood vinegars from different producers impacts
repellency efficiency. Of the tested constituents, acetic acid, furfural and ether-soluble (mainly aldehydes,
ketones, lignin monomers) and ether-insoluble (“wood syrup”) fractions of the water extract of wood vinegar
induced a clear repellent effect on snails, but their effects were considerably lower than the effect of wood
vinegar. Thus the repellent effect of wood vinegar is due to a larger set of its chemical constituents rather than
to a specific compound. All tested wood vinegars induced a clear repellent influence on snails, but differences
existed between the products of different retorts. These differences were at least partly due to differences in
the products’ organic material content. According to our studies, A. arbustorum can sense quality differences
between wood vinegars, even below 10% dilutions. We suggest that utilizing the avoidance behaviour of A.
arbustorum is an easy, non-costly method for monitoring the quality of slow pyrolysis liquids but also
hitherto unknown environmental contaminants.

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