![]() Nanotechnology is emerging as a highly attractive tool to achieve this goal by offering new methods for the formulation and delivery of active pesticide ingredients, as well as novel active ingredients, collectively referred to as nanopesticides. One of the critical challenges in the agricultural industry is the need to address issues associated with the pesticide’s use as environmental contamination, bioaccumulation, and increases in pest resistance, which demands a reduction in the quantity of pesticide applied for crop and stored product protection. In the last few years, the application of nanotechnology in agriculture has created new opportunities for developing nanosized agrochemicals that have the potential to improve efficiency, enhance stability, prolong the effective duration and at the same time reduce environmental loads. ![]() ![]() These results provide new tools for a comprehensive picture of the sulfonylurea environmental fate and toxicity of nicosulfuron in the environment. fluorescens strain SG-1 was also able to biotransform two other sulfonylureas (metsulfuron-methyl and tribenuron-methyl) with various novel pathways. The toxicity of metabolites (standardized Microtox® test) showed a 20-fold higher toxicity of ADMP than nicosulfuron. The extend and rate of formulated nicosulfuron transformation were considerably reduced compared to those with the pure active ingredient (appearance of a lag phase, 30% dissipation after 10 days of incubation instead of 100% with the pure herbicide) but the same metabolites were observed. Two-phase dissipation kinetics of nicosulfuron by SG-1 were observed at the highest concentrations tested (0.5 and 1 mM) due to biosorption. ![]() Four metabolites were identified among which ASDM (2-(aminosulfonyl)-N,N-dimethyl-3-pyridinecarboxamide) and ADMP (2-amino-4,6-dimethoxypyrimidine) in substantial proportions, corresponding to the hydrolytic sulfonylurea cleavage. This strain was identified as Pseudomonas fluorescens and is able to quantitatively dissipate 77.5% of nicosulfuron (1 mM) at 28 ☌ in the presence of glucose within the first day of incubation. A bacterial strain SG-1 was isolated from an agricultural soil previously treated with nicosulfuron. Nicosulfuron is a selective herbicide belonging to the sulfonylurea family, commonly used on maize culture. The various kinds of surfactants with a wide variety of molecular weight and ionic character as well as natural and petroleum oils are used as wetting, spreading, sticking, and penetration agents and humectants (Hazen 2000 Krogh et al. Among adjuvants, surfactants are some of the most important components and can improve the biological activity by modifying spray droplet size, retention, and spreading on leaf surfaces or by enhancing uptake and translocation of the a.i. ![]() A lower water solubility of the pesticide usually leads to utilization of a water-miscible organic solvent and formulation additives (adjuvants) including surface-active agents (surfactants) to solubilize, suspend, or disperse the active ingredient (a.i.) of pesticide in its aqueous solution being applied in agricultural practices. Many types of formulations have been developed by considering the physicochemical properties of the pesticide, not only to maximize their efficacy but also to prevent unfavorable environmental contamination from pesticide and its degradation products. Pesticides having a wide variety of structures have been and are being developed to exhibit an intended efficacy to pests, fungal diseases, and weeds, and are usually applied as formulations to these targets in the field. ![]()
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