Effects of plant extracts on the feeding behaviour of the slug Arion lusitanicus

Methanol extracts of the plants Geranium robertianum, Lepidium sativum, Ori ganum vulgare, Salvia officinalis, Salvia pratensis, Saponaria officinalis, Thymus vulgaris, Trifolium repens and Valerianella locusta were produced a nd applied to cotyledons of 6-8 days old rape seedlings to investigate whet her they can influence the feeding of the slug Arion lusitanicus on young r ape. All plant extracts appeared to reduce slug feeding on rape to some ext ent, but only the extracts of Saponaria officinalis and V. locusta signific antly deterred A. lusitanicus from feeding. The small effects of some extra cts may be due to a poor extraction efficiency or an insufficient feeding i nhibition capacity of these extracts.