Biocidal activity of polylactic acid-based nano-formulated abamectin on Acyrthosiphon pisum (Hemiptera: Aphididae) and the aphid predator Adalia bipunctata (Coleoptera: Coccinellidae).

Changjiao Sun,Frédéric Francis,Haixin Cui,François Verheggen,Zhanghua Zeng,Manli Yu

doi:10.1371/journal.pone.0228817

Abstract

Abamectin is a common biocide used to control agricultural insect pests. However, the water insolubility of abamectin may result in extra organic solvent introduced in the environment. To solve this issue, it is desirable to develop nanoformulations to encapsulate abamectin with environment-friendly polymers. In this study, two polylactic acid based abamectin nanoformulations were prepared. The average particle sizes, measured by dynamic light scattering and transmission electron microscope, were 240 nm and 150 nm, respectively. The insecticidal activity of these nano-formulated abamectin was examined in the laboratory on the pea aphid, Acyrthosiphon pisum (Hemiptera: Aphididae). The acute toxicity of nano-formulated abamectin on non-target aphid predator Adalia bipunctata (Coleoptera: Coccinellidae) was also evaluated by topical, residual and oral exposure. The two nano-formulated abamectin had comparable insecticidal effect with commercial abamectin formulation against the pea aphid. Taking median lethal concentration (LC50) as the toxicological endpoint, nanoformulations had higher contact toxicity and lower oral toxicity to first-instar larvae of the predator A. bipunctata. These results are expected to contribute to the application of solvent-free nano-formulated pesticides that comply with the integrated pest management (IPM) strategies.

Highlights

One of the global challenges faced by the agriculture industry is the sustainable food production for the rapidly growing human population, reaching 9.7 billion of individuals by 2050 [1,2]
Nanopesticide formulations may decrease the use of organic solvent and improve the biological efficacy of pesticides owing to the increasing dispersity, wettability, and penetration properties [6, 10]
The hydrodynamic size of Abam-Polylactic acid (PLA)-NS measured by dynamic light scattering (DLS) was 240.7±1.9 nm, and it increased to 243.6±1.2 nm for the Abam-PLA-Tannin-NS

Summary

Introduction

One of the global challenges faced by the agriculture industry is the sustainable food production for the rapidly growing human population, reaching 9.7 billion of individuals by 2050 [1,2]. In order to avoid the well-documented deleterious effects of pesticides, the efforts of agrochemical industry are focused on looking for new active substances, and in new pesticide formulations [4]. During the last two decades, nanotechnology has been considered to have the potential to lead revolution in agricultural practices, especially in agrochemicals [5,6]. The development of nanotechnologies applied to pesticide formulations has facilitated the safe application of conventional pesticides by achieving precise and targeted delivery [7,8,9]. Polymer-based nanoformulations are regarded as having the greatest potential for further development and practical application, due to their biocompatibility, biodegradability, modifiability and miscibility properties [10,11,12,13]

Methods

Results

Conclusion