Experiments on feeding rate of Deroceras reticulatum (O. F. Müller) and damage caused by this slug to oilseed rape and other plant species were carried out under laboratory conditions. No-choice tests were conducted on 20 plant species at the growth stage of 2–3 leaves. The percentage of plant damage was assessed in consecutive days of the slug feeding and the consumption index (C.I.) was calculated for each plant species and for slugs of known weight. The slug feeding rates varied significantly between the examined plant species. Papaver argemone, Sisymbrium officinale and Erigeron canadensis were the most sensitive to the slug feeding, Geum urbanum, Seneico vulgaris, Epilobium palustre and Impatiens roylei – the least so.