Increasing introductions of non-native terrestrial slugs (Mollusca: Gastropoda) are a concern to North American regulatory agencies as these generalists impact the yield and reduce the aesthetic value of crop plants. Understanding how the increase in diversification in North American cropping systems affects non-native gastropods and finding effective biological control options are imperative for pest management; however, little research has been done in this area. This study tested the hypothesis that dietary diversification affects the biological control capacity of a generalist predator and allows the slug pest Deroceras reticulatum (Müller) (Stylommatophora: Agriolimacidae) to more effectively fulfill its nutritional requirements. Results showed no significant correlations between dietary diversification and slug development; however, this was likely due to the addition of romaine lettuce to all treatments. The study also showed that dietary diversification had no significant effect on D. reticulatum egg production, with self-fertilizing slugs consistently having significantly higher egg production than outcrossing slugs. Most significantly, this research demonstrated reductions in plant damage by D. reticulatum in treatments containing the North American carabid beetle Scarites quadriceps Chaudoir (Coleoptera: Carabidae) with the presence of alternative prey having no effect, supporting its use in biological control efforts in spite of its generalist feeding habits.