Aim: Micro encapsulation of diclosulam herbicide was done in xanthan gum based polymeric system through ionotropic gelation method to formulate a slow-release herbicide to achieve prolonged weed control in irrigated upland ecosystem. Place and Duration of Study: The slow-release formulation of diclosulam was synthesized and characterized in the Department of Nano Science & Technology, Tamil Nadu Agricultural University during January to July 2022. Methodology: Xanthan gum- alginate microsphere system was synthesized with varying concentrations of calcium chloride (CaCl2) (2, 4 and 6 per cent) to encapsulate diclosulam through ionotropic gelation. The size, entrapment efficiency, pore volume, pore radius, surface area and swelling behavior of microspheres were assessed to achieve higher loading of diclosulam and good stability of microspheres. Results: The mean diameter of xanthan gum-alginate microsphere was higher with 6 per cent ion gelation bath followed by the concentration of 4 and 2 per cent. Higher entrapment efficiency of diclosulam was achieved with loading of two percent diclosulam in six per cent calcium crosslinked microspheres. Conclusion: Xanthan gum-alginate microsphere system offers both burst release and controlled release of active ingredients. However, controlled release polymeric templates with herbicide will synchronize the release of herbicide with the emergence of weeds in the cropped situations for better weed management.

Weeds are unwanted plants, which interfere with the crop production. Weeds compete with crops for resources, causing severe yield loss. Chemical weed control through herbicides is a quite effective and reliable strategy to manage weeds. Herbicides constitute a major share of the global pesticide market. However, the applied herbicides undergo losses in the agroecosystem in different ways (chemical degradation, microbial decomposition, photo-degradation, leaching, run-off, and volatilization), thus lowering the herbicidal action coupled with contaminating ecosystem and groundwater. Encapsulation of herbicides is an innovative approach that addresses issues associated with the application of herbicides for controlling weeds. Encapsulation represents the embedding of an active ingredient in shell of polymeric material to achieve the controlled release of the active ingredient at the desired rate. The encapsulation of herbicides enhances stability, solubility, and bioactivity and alters the release pattern of herbicide resulting in improved weed control efficiency. Further, encapsulation lowers the application rate of herbicides, which in turn reduces the residue carryover of herbicide in soil and minimizes the environmental hazards. Therefore, encapsulated herbicide formulation has greater significance in the future weed management and will become ground-breaking technology in the chemical era of weed control.

Aims: The study's objective is to develop lignosulfonate-based nanocarriers as a UV protectant for agrochemical delivery Place and Duration of Study: Department of Nano Science & Technology, Tamil Nadu Agricultural University, Coimbatore. The research was carried out between March 2021 and January 2022. Methodology: We demonstrate a straightforward approach for the solvent – anti-solvent conversion of lignosulfonate macromolecules from black liquor derived from the paper pulping industry to nanocarriers. Due to the amphiphilic nature of lignin, nanoparticles are generated by self-assembly. To create lignin nanoparticles, a drop-by-drop solvent exchange approach has been used. The lignosulfonate solution was prepared using solvents such as ethanol and tetrahydrofuran, and then water was added as an antisolvent, resulting in the creation of nanoparticles by self-assembly. The hydrophobic portion of lignin creates the particle's core, while the hydrophilic hydroxyl groups form the particle's shell. The size and stability of nanoparticles were determined using dynamic light scattering, and the form and size of the systems were imaged using scanning electron microscopy. The functional groups of the nanoparticles were determined using Fourier transform infrared spectroscopy. Results: Solvent tetrahydrofuran generated uniform and spherical lignosulfonate nanoparticles than the solvent ethanol employed in the solvent exchange procedure. When ethanol and cetyl trimethyl ammonium bromide were used as solvent and surfactant, respectively, the size of lignosulfonate nanoparticles was smaller (270±31.9nm). However, the stability of nanocarrier systems was unaffected by the solvent used, with polydispersity index values of 0.435±0.003 and 0.401±0.028 for tetrahydrofuran and ethanol solvents, respectively. The existence of a distinctive peak at 526 and 609 cm-1 in the infrared spectrum corresponding to sulfonic stretching indicated the presence of lignosulfonate in the carrier systems. Conclusion: Lignosulfonate-based nanocarrier systems were developed using the solvent exchange method. However, the nanocarrier systems are to be validated to assess the bioefficacy of active molecules.