Herein, nanostructured metal oxides of essential soil nutrient elements (i.e., CuO and CaO) with definite shape and size were simply synthesized, and their pesticidal activities against cotton leafworm ( Spodoptera littoralis) were explored for the first time. These metal oxide nanostructures represented novel economic and ecofriendly nanopesticides for sustainable plant protection and might boost the nutrient content of soil. The results showed that CuO nanoparticles (NPs) and CaO NPs exhibited potential entomotoxic effects against S. littoralis. Interestingly, CuO NPs exhibited fast entomotoxic effect with LC50 = 232.75 mg/L after 3 days, while CaO NPs showed a slow entomotoxic effect with LC50 = 129.03 mg/L after 11 days of post-treatments. The difference in the pesticidal activity of the metal oxides is related to their physical characteristics and interfacial surfaces upon insect midgut and cuticle layer of insect body wall. Thus, nanoengineered metal oxides might be utilized to generate an alternative and cost-effective pesticide formulation in the near future.

Herein, silica nanostructures with various physicochemical characteristics were synthesized via surfactant-assisted methods. Potent entomotoxic effects of silica nanostructures were explored against cotton leaf worm (Spodoptera littoralis) for the first time by utilizing surface contact and feeding bioassay protocols. The mortality of the treated larvaes by surface contact was faster than feeding bioassay method. The results showed that the surface characteristics and particle size of silica nanostructures could effectively control their entomotoxic effects compared to commercial silica or even organic pesticides. It was also observed that the dead bodies of the insects became extremely dehydrated due to the damage of insect cuticular water barrier as a result of abrasion. Furthermore, the physical mode of action of silica nanostructures makes insects is unlikely to become physiologically resistant; hence, silica nanostructures can be efficiently used as a valuable tool in S. littoralis management programs.

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The present investigation aimed to throw light on the efficiency of two novel insecticides, pyridalyl and emamectin benzoate(contact), a semi-synthetic insecticide on two different larval instars (2 nd and 4 th) of the cotton leafworm, Spodoptera littoralis (Lepidaptera: Noctuidae). Also to study their toxic affects on some biochemical parameters on albino rat. The results clearly showed that pyridalyl was more toxic than emamectin benzoate against the 2 nd and 4 th larval instar according to LC 50 values after all time post exposure (2, 3, 5 and 7 days). In addition the two tested compound decreased pupal weight, pupation and adult emergence percentages resulted from larvae treated with different concentrations of these insecticides as 2 nd and 4 th larval instars. The present study also animals were treated orally with (1/10 LD 50) of each compound done by using sixty male adult albino rats were divided into three groups .First group "control" was received distilled water daily, second group were received repeated oral administration of 0.07mg/animal/day of pyridalyl and third group were received repeated oral administration of 2.5 mg/animal / day of emamectin benzante for 28 consecutive days. The results showed that there were significant increases of ALT, AST, urea and creatinine in the treatment of Pyridalyl more than emamectin benzante and control. On the other hand there were significant decreases in protein content in the treatment of Pyridalyl more than E. benzante on comparison with control. Conclusion: The results indicated the toxic nature of the insecticide pyridalyl is more than E. benzante on Spodoptera littoralis and albino rats so we suggest that usage of E. benzante although it less toxic to save environment.