Observations of field slug activities in Switzerland in relation to weather conditions
Abstract: Over the last years the slug activity-density (method: Glen et al., 2003) was monitoredfrom early spring to midsummer (growing season) in a no-tillage plot and a plot withconventional plough tillage in the “Oberacker” long-term field trial of the Office of SoilProtection at the Inforama Ruetti in Zollikofen (Switzerland). In a first evaluation the numbers ofobserved animals were compared with the weather conditions over these years. In this study theparameters of the over-wintering conditions for slugs are investigated. The main factorsinfluencing the over-wintering populations are also found to be soil temperature and soil matrixpotential. Soil temperatures lower than +3° C of water saturated soils reduce the surviving chanceof slugs and snails in winter. In periods with favourable weather conditions for slugs the slugactivity density reacts faster and reaches higher values in the no till plots.