Compatibility of Egyptian strains of entomopathogenic nematodes (Nematoda: Rhabditida) with insecticides and their activity against Spodoptera frugiperda (Lepidoptera: Noctuidae) under laboratory conditions.

Under laboratory conditions, the activity of two entomopathogenic nematodes, Heterorhabditis bacteriophora (HP88) and Steinernema carpocapsae (AT4), as well as their compatibility with two common insecticide formulations (lambada cyhalothrin and flubendiamide) and one insect growth regulator (lufenuron), were evaluated against Spodoptera frugiperda . The nematode IJs were subjected to the LC 50 and LC 25 of insecticides, and the viability of infective juveniles (IJs) was measured before being tested against Galleria mellonella larvae to determine IJs pathogenicity. Also, the mixtures were evaluated against the 4 th instar larvae of S. frugiperda to select one mixture can serve in integrated pest management (IPM) in agro-ecosystems. Results showed that H. bacteriophora strain (HP88) was more efficient with higher pathogenicity and virulence against 4 th larvae of S. frugiperda (LC 50 = 48.67±0.34IJs/ml -1 ) than S. carpocapsae (AT4) (LC 50 = 65.88± 3.04). flubendiamidee was the most toxic insecticide (LC 50 = 3.26±0.52) followed by Lambada cyhalothrin (4.23±0.8PPM).