Abstract
BackgroundNanomaterials in plant protection promise many benefits over conventional pesticide products. Nano-enabled pesticides may alter the functionality or risk profile of active ingredients. Cationic nanochitin whiskers (NC) possess strong biological activity against wheat aphids. However, toxicity and synergistic effects of NC with chemical pesticides against pest insects has not been systemically reported. This study investigated the insecticidal enhancement by NC with Omethoate (40% EC), Imidacloprid (10% WP), and Acetamiprid (40% WG) for pest control using wheat aphid as piercing-sucking mouthparts insect. Fluorescein isothiocyanate labelled NC was used to monitor the uptake and transportation pathway of NC inside the target insects. Toxicity of NC was tested with Sprague-Dawley (SD) rat. Our findings provide a theoretical basis for future application of NC in plant protection against pest insects.ResultsNCs synthesized by acidic hydrolysis were rod-like nanoparticles in a range of 50–150 nm in length and 30–50 nm in width, which examined by electron microscopy and dynamic light scattering methods. The charge density and zeta potential were about 63 mmol/kg and + 36.4 mV, respectively. By absorption and/or contact action of 30–50 mg/L of NC suspension, the corrected mortality of wheat aphids reached up to 80% or above after 12 h treatment, NC could be distributed through digestive system and relocated from mouth to other tissues inside the insect body. When associated with dilutions of conventional pesticides, the corrected mortality were significantly increased up to 95% or above. The dosage of the chemical pesticide and nanochitin in the mixtures (1:1 by volume) were all reduced to half. The acute oral toxicity Lethal Dose 50% (LD50) to SD rat is greater than 5000 mg/kg BW (body weight) in male and female, acute dermal toxicity LD50 is greater than 2000 mg/kg BW of NC.ConclusionsNC has a strong promotive effect on insecticidal effectiveness of chemical insecticides. It was easily absorbed by plant, transported and distributed from mouth to other tissues of the insects while sucking plant fluid. Low acute oral and dermal toxicity to SD rat indicated that it is safe to apply in agriculture and food industry. NCs has a great potential for water-based nanopesticide formulation to reduce chemical pesticide use for future agro-environmental sustainability.
Highlights
As a recognized cutting edge technology, nanotechnology has been applied across a wide range of areas, perhaps more recently in the natural sciences with significant interest in agriculture and food applications over the past decades [1, 2]
Based on dynamic light scattering (DLS) analysis, 90% of the nanoparticles in this study were in the range of 37.3 to 140.0 nm (Fig. 2, left) with a PDI of 0.247, showing that the nanochitin whiskers have a high dispersibility in aqueous solution
Our results showed that the acute oral and dermal toxicity LD50 were nontoxic to the tested mice at a concentration of 0.3% (w/v, 3,000 μg/mL), which makes a good agreement with previous study done by Zhao et al [47]
Summary
As a recognized cutting edge technology, nanotechnology has been applied across a wide range of areas, perhaps more recently in the natural sciences with significant interest in agriculture and food applications over the past decades [1, 2]. The advantages of the application of nanomaterials in agriculture are in particular to improve pesticides activity, enhance the yield and quality of crops, reduce agrochemicals usage and cost in plant protection, minimize nutrient losses in fertilization, and scale down the environmental pollutions [4, 5]. Nanoparticles may act as plant growth promotors, and/ or enhancers for stress tolerance to harsh environment. Their functionality and efficacy depend on their physiochemical properties, and application methods (foliar delivery, hydroponics, soil). Liu et al.[8] proposed that nano-scaled formulation of pesticide provided a better spatial distribution of the pesticide and uniformity of coverage on leaf surfaces during enhancing the insecticidal efficiency. Our findings provide a theoretical basis for future application of NC in plant protection against pest insects
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
