Use of Lignins from Sugarcane Bagasse for Assembling Microparticles Loaded withAzadirachta indicaExtracts for Use as Neem-Based Organic Insecticides

Eveline S Costa,João B Fernandes,Andreia P Matos,Bruno Perlatti,Caio M P Da Silva,Moacir R Forim,Everton M Da Silva,Vânia G Zuin,Maria Fátima G F Da Silva

doi:10.5935/0103-5053.20160155

Eveline S Costa, João B Fernandes + Show 7 more

Open Access

https://doi.org/10.5935/0103-5053.20160155

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Abstract

Microcapsules of sugarcane bagasse lignin loaded with organic extracts of neem (Azadirachta indica) were prepared and evaluated as potential bioinsecticides. Lignins were extracted and modified by oxidation and acetylation reactions providing different biopolymers. Afterwards, they were characterized through several analytical techniques. The formulations were initially prepared as colloidal suspension of lignin nanoparticles, which were then spray-dried. The products were submitted to quality control protocols using high performance liquid chromatography (HPLC), thermal and photochemical degradation studies, followed by biological assays against Spodoptera frugiperda and Diatraea saccharalis. The formulations showed increases in both thermal and photo stability of approximately 40% compared with control samples. All the formulated microparticles were efficient against the insects evaluated and required a shorter time to achieve 100% mortality than the controls. The use of sugarcane bagasse lignins to prepare microparticles improved the resistance of neem extracts against abiotic factors, retaining the biological activity of this biopesticide.

Highlights

Insect pests have an important effect on the efficient production of food and animal feeds worldwide, demanding robust control strategies that depend on synthetic agrochemicals.[1]
This study aimed to develop a new environmentally friendly biopesticide containing azadirachtin-rich neem extracts and formulations encapsulated in nano- and microparticles prepared using lignins from sugarcane bagasse
The phenolic acid moieties present in lignin structures are known for their antioxidant properties and may provide photo and thermal stability, properties that are of great interest regarding to prolonged and controlled release.[27,28]

Summary

Introduction

Insect pests have an important effect on the efficient production of food and animal feeds worldwide, demanding robust control strategies that depend on synthetic agrochemicals.[1]. Significant production, regulation, and enforcement problems must be overcome, to obtain commercially viable biopesticides. Their stability during storage and the reproducibility of their effectiveness must be evaluated before they can be reliably marketed. One of the main limitations in the use of natural products for crop protection is their short residual period, where several extrinsic factors may affect the stability of the product or the active natural compound. Results from field experiments have shown that crude A. indica extracts applied to crops only remain active for 3 days.[4] Environmental

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