Entomotoxic effect of silicon dioxide nanoparticles on Plutella xylostella (L.) (Lepidoptera: Plutellidae) under laboratory conditions

ABSTRACT

The use of higher dosage and repeated applications of conventional pesticides have led to the rapid development of insect resistance to pesticide and adverse effects on human health and environment. Accordingly, researchers are prompted to identify an alternative entomotoxic agent for crop protection. Nanocides are being considered as alternatives to conventional insecticides because they are expected to lessen the application rate and reduce the chances of resistance development in pests. In this study, we evaluated the entomotoxic effects of nanosilica on larvae of Plutella xylostella, in a laboratory by using dust spray, larva dipping, leaf dipping, and solution spray methods. Dust treatment showed a more highly significant effect than the other three treatments. The mortality percentage increased up to 58% and 85% at 24 and 72 h after treatment, respectively, when nanosilica was applied at a rate of 1 mg cm⁻². In all four bioassays, mortality rate increased with both increased time after nanosilica exposure and increased concentration. Light microscopy and scanning electron microscopy images showed that larval death was due to desiccation, body wall abrasion, and spiracle blockage. These results suggested that nanosilica can be an alternative to conventional pesticides if dust formulation would be properly used.

KEYWORDS:

• Silicon dioxide
• nanoparticles
• nanosilica
• Plutella xylostella
• entomotoxicity

Acknowledgments

We are very grateful to Prof. and Dr Lin Dao-hui for his help in designing nanosilica in his ‘Nanotechnology and Environmental Lab’ at Zhejiang University, and Dr Faisal Islam of the College of Agriculture and Biotechnology, Zhejiang University, for providing unlimited help during the experiment.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

We acknowledge the National Basic Research Program of China (973 Program) [grant number 2009CB119005], [grant number 2006CB102005]; the National 948 Program [grant number 2011-G4]; the National Department Benefit Research Foundation [grant number nyhyzx20110321] for their generous financial support to this research.