Biological control of cabbage fly Delia radicum with entomopathogenic nematodes: selecting the most effective nematode species and testing a novel application method

•We tested the efficacy of four entomopathogenic nematode species against cabbage fly CF.•Steinernema feltiae provided the best results for controlling CF infested radishes.•Nematodes in alginate beads gave better results than nematodes in suspension.•Nematodes in alginate beads worked better even in lower doses than in suspension.•The application of empty beads without nematodes also mitigated CF infestation.