An environmentally friendly, rainfall-resistant suspension prepared based on halloysite nanotubes for the delivery of hydrophobic pesticides

Abstract

The application of nanomaterials in pesticide system shows many advantages such as enhanced dispersion stability, high foliar affinity, improved insecticidal effect, and reduced environmental risks. In the study, a simple wet grinding method was used to decrease the particles size of the pesticides chlorobenzuron and indoxacarb (CI) in presence of halloysite nanotubes (HNTs). The irregularly shaped suspension pesticide system (CI@HNTs) in size of ∼ 2 μ m is obtained via HNTs and xanthan gum (XG) encapsulation of the hydrophobic pesticides. Attributed to the small size and interfacial interactions of HNTs, CI@HNTs have excellent stability, dispersion and slow release behavior. CI@HNTs exhibit enhanced foliar wettability, spreading and topological effect on plant leaves compare to commercial suspension concentrate (SC) product and CI (without HNTs), which results in high resistance to rainfall washout. In the crop model treated by fall armyworm, the mortality rate is 53.3 % in CI group, while the mortality is 75.0 % in CI@HNTs-8 which is 1.41 times that of CI. In addition, the safety of CI@HNTs is systematically evaluated, and the results show that the toxicity of CI@HNTs to the wheat and the aquatic organism zebrafish is lower than that of the SC. This study develops an economical, efficient and environmentally friendly pesticide system based on natural clay nanotubes, which shows promising applications in sustainable agricultural production.