Slugs Deroceras reticulatum (O. F. Müll.), Deroceras laeve (O. F. Müll.) and Lehmannia valentiana (Fér.) were tested for their susceptibility to infection with a nematode Phasmarhabditis hermaphrodita (Schneider). D. reticulatum was the most susceptible, D. laeve much less so, while L. valentiana was not attacked by the parasite. Ph. hermaphrodita may be used for slug control, but not all slug species are equally susceptible.