Nanochitin whisker enhances insecticidal activity of chemical pesticide for pest insect control and toxicity

Abstract

Background Nanomaterials 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. Results NCs 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. Conclusions NC 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.

Nanochitin: Chemistry, Structure, Assembly, and Applications

“…Nanochitin can be used as a functional additive or nanofiller, ,− by taking advantage of the inherent chemical, morphological, and biological features of nanochitin, e.g. , surface charge and chemistry, anisotropy, flexibility, fibril dimension, aspect ratio, and nitrogen content. − Hence, nanochitin enables novel material design, for instance, to reinforce different materials, , and as a biomimicry template of periodic structures (ChNC LCP). ,, This takes advantage of the combination of nematic structural properties of ChNC and a reinforcing phase to create advanced materials, showing potential uses in sensing, electrochemical, and optical applications, among others. ,,,, Templating ChNC LCP was used to synthesize silica-based mesoporous nitrogen-doped carbon films in a layered nematic organization (Figure a) . By transferring the long-range ordered organization of helicoidal ChNCs to the solid phase, a carbon film was produced and used as electrode in a supercapacitor that showed an improved electrochemical performance (Figure a).…”

Chitin, Chitosan, and Nanochitin: Extraction, Synthesis, and Applications

“…Chitin nanowhiskers conjugated to biopesticides have been demonstrated to improve the effectiveness of the pesticides versus insects with sucking mouthparts, such as aphids [ 140 , 141 ]. Isolated nanowhiskers displayed low dermal and oral toxicity in a rat model, though no comparison was made to those conjugated to pesticides [ 140 ].…”

Toxicity and Behavior-Altering Effects of Three Nanomaterials on Red Imported Fire Ants and Their Effectiveness in Combination with Indoxacarb

“…In addition, when combined with chemical pesticides, the dosage of both agents can be reduced by half without a significant decrease in activity. The presence of nano-chitin whiskers greatly enhances the effectiveness of chemical insecticides in killing insects while also reducing the rates of pupation and emergence [38]. The MON@CeO 2 nanohybrid, based on CeO 2 , functions as an inhibitor of reactive oxygen species (ROS) that greatly enhances the toxicity of nitenpyram, sulfadiazine, and clothianidin, which are brown planthopper-resistant insecticides in both laboratory and field settings.…”