Ernat Received: ten September 2021 Accepted: 2 October 2021 Published: four OctoberZoology Division, Faculty of Science, Tanta University, Tanta 31527, Egypt Botany Division, Faculty of Agriculture, Menoufia University, Shibin El-Kom 32514, Egypt; [email protected] Plant Production Division, College of Food and Agriculture Sciences, King Saud University, P.O. Box 2460, Riyadh 11451, Saudi Arabia Department of Crop Sciences, Faculty of Agriculture, Menoufia University, Shibin El-Kom 32514, Egypt Department of Biology, College of Science, Taif University, P.O. Box 11099, Taif 21944, Saudi Arabia; [email protected] Division of Economic Entomology and Agricultural Zoology, Faculty of Agriculture, Menoufia University, Shibin El-Kom 32514, Egypt; [email protected] Correspondence: [email protected] (H.E.); [email protected] (M.F.S.)Easy Summary: Food safety would be the people’s principal concern, and agricultural crops play a important role in ensuring it. Agricultural pests, alternatively, are regarded one of many most significant threats to bring about a substantial difficulty for meals safety. Entomopathogenic nematodes in the genera Herterorhabditids and Sterinernematids fulfil the basic requirements of perfect bio-control agents; even so, their efficacy largely dependent on their symbiotic bacteria. As a result, this study aimed to investigate the capacity of your isolated symbiotic bacteria (Photorhabdus and Xenorhabdus) to manage Pieris rapae and Pentodon algerinus larvae in comparison with their own nematodes, Heterorhabditis bacteriophora and Steinernema riobravis, respectively. The results showed that each nematode species and their symbiotic bacteria had been in a position to suppress both insect species. On the other hand, each bacterial genera have been far more effective than the investigated nematode species against P. rapae, while nematodes have been superior against P. algerinus. Gas chromatography ass spectrophotometry of Xenorhabdus sp. and Photorhabdus sp. identified the key components with all the insecticidal properties. The two bacteria genera have been established to be secure and had no substantial impact on normal WI-38 human cells. In conclusion, the symbiotic bacteria might be employed safely and proficiently against the tested insects independently on their own entomopathogenic nematodes. Abstract: Pieris rapae and Pentodon algerinus are regarded as a Pipamperone custom synthesis global threat to agricultural crops and meals safety; therefore, their manage is often a vital concern. Heterorhabditid and Steinernematid nematodes, as well as their symbiotic bacteria, can reach the optimal biocontrol agent criterion. For that reason, this study aimed to evaluate the efficacy of Heterorhabditis bacteriophora, Steinernema riobravis, and their symbiotic bacteria (Xenorhabdus and Photorhabdus) against P. rapae and P. algerinus larvae. The virulence of entomopathogenic nematodes (EPNs) was determined at distinct infective juvenile concentrations and exposure instances, even though the symbiotic bacteria had been applied at the concentration of three 107 colony-forming units (CFU)/mL at diverse exposure times. Gas chromatography ass spectrophotometry (GC-MS) analysis along with the cytotoxic impact of Photorhabdus sp. and Xenorhabdus sp. have been determined. The outcomes indicated that H. bacteriophora, S. riobravis, and their symbiotic bacteria substantially (p 0.001) induced mortality in each insect species. However, H. bacteriophora and its symbiont, Photorhabdus sp., have been additional v.