The cotton leafworm Spodoptera littoralis is the most devastating insect pests to many crop plants. The overuse of pesticides increased their resistance in all pests. This study has been devote to develop a novel synthetic scheme to produce pesticide nanocomposite of very high efficiency compared to its original ones. The method is based on using silver nanoparticles (AgNPS) as a pesticide carrier by loading the pyrethroid pesticide Lambda-cyhalothrin (L-CYN) into the surface of prepared AgNPS. The nature of binding has been investigate via TEM and FT-IR techniques. The new formulation of the pesticide nanocomposite AgNPS@L-CYN has been teste for its larvicidal activity against second instar larvae of lab and field cotton leafworm. Our findings indicate that silver lambda-cyhalothrin nanocomposite is more effective on cotton leafworm larvae than that of formulated lambda-cyhalothrin alone. The required concentration for control of cotton leafworm decreased more than 37 times. This approach might be successful ones for decreasing the resistance of this pest to pesticides and reduce environmental pollution.