Synthesis and characterization of silica nanostructures for cotton leaf worm control

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.