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 eco:friendly nano:pesticides for sustainable
plant protection and might boost the nutrient content of soil. The results showed that CuO
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 mid:gut and cuticle layer of insect
body wall. Thus, nano:engineered metal oxides might be utilized to generate an alternative
and cost effective pesticide formulation in the next future.