Efficacy of Nano-Encapsulated Mandarin Oil using (Polyethylene Oxide/Polyacrylamide) and Gamma Irradiation against Culex pipiens Larvae

Nano-encapsulation of essential plant oils may prove to be the most effective approach to overcome their application challenges against insect pests. Larvicidal properties of polyethylene oxide/polyacrylamide (PEO/PAAM) nanogels of mandarin essential oil (MEO) against Culexpipiens larvae were investigated. The nano-gel was prepared using an intramolecular crosslinking method initiated by gamma irradiation. The resulting mandarin essential oil (PEO/PAAm) nanogel (MEON) exhibited monodispersity, a relatively small size distribution, and a low negative surface charge of -1.1 mV, suggesting enhanced stability and reduced electrostatic interactions. The 2nd instar larvae were more sensitive to MEON than the 3rd and 4th instar larvae at the lower doses of 10 and 15 ppm. The LC50 and LC99 for the MEON were (11.5 and 18.4 ppm) for 2nd instar larvae; (14.5 and 23.6 ppm) for 3rd instar larvae; and (15.3 and 33.8 ppm) for the 4th instar larvae, respectively, at 48 hours after treatment. These results shed light on MEON's physical attributes, surface qualities, and biological assay and suggest that it might be a useful substance for Culex pipiens management.