![]() Materials and Methods Soybean Looper Insect Colony MaintenanceĬhrysodeixis includens (Walker), LSU1, originally collected from south Louisiana in 1976 ( Newsom et al. This study increases understanding of the use of novel nanoscale biopolymer carriers as part of sustainable precision agriculture. To evaluate adsorption and coverage, residual levels of MFZ were measured at different time points. Efficacy over time was evaluated under field conditions by sampling soybean leaf tissue at different intervals post-spraying and feeding them to the soybean looper, Chrysodeixis includens (Walker). Thus, formulations of (+)ZNP(MFZ) were compared to a formulated commercial insecticide with the same active ingredient, Intrepid 2F at equivalent MFZ concentrations. However, those trials were conducted under laboratory conditions and field applications of (+)ZNP(MFZ) have yet to be conducted in order to demonstrate future applicability. Previous research has suggested that positively charged zein nanoparticles with entrapped MFZ may have greater deleterious effects on soybean lepidopteran defoliators than MFZ ( Bonser et al. To address these deficiencies, an experiment evaluating the biopolymer zein, a protein extracted from maize, as a nanodelivery system for methoxyfenozide (MFZ) was conducted. However, the impact of these nanoparticles in delivering agrochemicals is rarely evaluated in field studies. Biopolymer nanoparticles are degradable ( Vroman and Tighzert 2009) and have been evaluated as successful insecticide delivery agents in laboratory conditions ( de Oliviera et al. Environmentally safe and sustainable replacements for metal nanoparticles are needed and biopolymer nanoparticles have attracted increasing interest. 2021), and although these materials show promise in agriculture, concerns regarding unintended consequences exist, such as the accumulation of particles or ions in select environmental and biotic compartments, as well as a potential enhanced ability to penetrate cellular membranes ( Ahamed et al. Most agricultural nanoparticle research is focused on the use of inorganic nanoparticles ( Nel et al. Thus, nanoparticles could improve insecticide applications and reduce environmental pollution by delayed or even tunable release of active ingredients and selective targeting. Nanoparticles are agglomerations of materials, normally in the range of 1–100 nm, with increased surface area to volume ratios, resulting in functional characteristics divergent from their bulk counterparts ( Auffan et al. Nanoparticles as nanocarriers have the potential to increase insecticide delivery by improving or controlling absorption, coverage, and permeability while protecting insecticides from abiotic conditions and extending efficacy through slow release ( Hou et al. When insecticides are applied to plants, much of the product does not reach the intended target pest ( Pimentel 1995, Wang et al. The multiyear study results demonstrate that nanoparticles loaded with MFZ are comparable to Intrepid 2F under field conditions, with potential short-term benefits. Higher concentrations of MFZ were present in (+)ZNP(MFZ)-treated in leaf tissue at 3 d following spray when compared to Intrepid 2F. Regression analysis found no differences in mortality slopes between positively charged zein nanoparticles loaded with methoxyfenozide and Intrepid 2F, suggesting comparable efficacy of the synthesized nanoparticles to a commercial product. ![]() ![]() A separate set of leaves was sampled to measure residue levels of methoxyfenozide (MFZ) over time following foliar application using QuEChERS extraction and high-resolution liquid chromatography-mass spectrometry. Chrysodeixis includens (Walker) was used as a model and was fed sprayed soybean leaves to evaluate efficacy of the tested foliar products over time. Positively charged zein nanoparticles (empty and loaded with methoxyfenozide) were compared to the formulated product, Intrepid 2F, as a foliar spray in-field on soybean. We conducted a series of experiments using a biopolymeric nanoparticle synthesized from zein, a biodegradable maize protein, to compare efficacy of a nanodelivered hydrophobic insect growth regulator (methoxyfenozide) against a commercial formulation. Biopolymeric nanoparticles as nanocarriers have the potential to improve insecticide efficacy by improving absorption, coverage, and permeability while protecting the insecticide active ingredient from abiotic conditions and extending efficacy through controlled release. When insecticides are applied in the environment, much of the product does not reach the target pest.
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