Compatibility of five different entomopathogenic nematode (Nematoda: Rhabditida) species with registered insecticides and fungicides under laboratory conditions

Abstract: To increase our knowledge on the susceptibility of entomopathogenic nematode (EPN) species to agrochemicals, the compatibility of the infective juveniles (IJs) of the Steinernema feltiae, S. carpocapsae, S. kraussei, Heterorhabditis bacteriophora and H. downesi with 6 chemical, one plant-based and one bio-insecticide, and 13 synthetic organic and two inorganic fungicides were investigated under laboratory conditions. The effect of direct IJ exposure to insecticides for 6 and 24 hours was tested in Petri dishes at 15, 20 and 25 °C. In our experiment we determined the best compatibility of S. feltiae with active ingridients azoxystrobin, azadirachtin, Bacillus thuringiensis var. kurstaki and imidacloprid. The present study showed that S. carpocapsae and S. kraussei are sensitive to all tested insecticides, while H. bacteriophora is sensitive only to abamectin and lufenuron. Nematode H. downesi significantly suffered the highest mortality when infective juveniles were mixed with active ingredients (a. i.) tebuconazole, spiroxamine, and triadimenol. Based on our research, we conclude that compatibility is not only a species-specific but also a strain-specific characteristic.