L. valentiana has a life cycle similar to D. laeve. However, the ability of this species to lay eggs is not reached by the slug earlier than after one year of age. The time span of slug emerging from one batch provides some kind of protection of this species against the possible negative conditions, similarly as it is the case with other slugs. We conclude, therefore, that the Phasmarhabditis hermaphrodita nematode has potential as a biocontrol agent against D. laeve but not against L. valentiana.