Development and Evaluation of a Controlled Release System of TBH Herbicide Using Alginate Microparticles

Abstract

The development of controlled delivery system formulations has received increasing interest in the agriculture area. Tebuthiuron (TBH) is the most commonly used herbicide for weed control in sugar cane and cotton crops. The TBH and some of its metabolites are detected in surface water by leaching process, evidencing contamination and the need for an efficient process to decrease pesticide residues. The development of a controlled system release appears as a good solution. The present investigation aimed to study the development and evaluation of alginate microparticles as a delivery system for the TBH. The calcium alginate microparticles were prepared from the crosslinking of sodium alginate by Ca ++ containing varied amounts of TBH supplied in CaCl 2 aqueous solution. The particle size and morphological analysis of microparticles were determined by optical microscopy (OM) and by field emission gun scanning electron microscopy (FEG-SEM). The encapsulation efficiency and release of TBH studies was accessed by UV-vis spectroscopy. The results show that the polymeric microparticles containing TBH can be obtained successfully through a simple method and is suitable as a controlled release carrier system for herbicides and can be effective for controlling weeds.

Controlled Release of TBH Herbicide Encapsulated on Ca-ALG Microparticles: Leaching and Phytointoxication Plants

“…For the encapsulation of the TBH herbicide in the alginate microparticles, predetermined amounts of the commercial Combine® 500 SC formulation (4 g L -1 , 6 L -1 and 8 g L -1 ) were prepared at 3% (m/v) of alginate solution. The microparticles of Ca-ALG containing the herbicide TBH were obtained by ionotropic gelation, according to the methodology described by Faria et al (2016). The obtained microparticles were stored in deionized water and underwent a water exchange process for a period of 3 days.…”

“…This procedure was adopted in order to remove as much NaCl as possible from the Ca-ALG microparticles. After this, the Ca-ALG microparticles were oven-dried at a temperature of 35 o C for a period of 24 h, according to Faria et al (2016) and Dourado Júnior et al (2017). Further information regarding the characterizations used in the microparticles of Ca-ALG and the kinetics of release containing the herbicide TBH can be obtained in the work of Faria et al (2016).…”

“…This herbicide is applied in pre-emergence in the cultivation of sugarcane, and used for control of mono and dicotyledonous species. As its final destination is the soil, according to Fontes et al (2004), Wang et al (2008), Tomco et al (2010) and Faria et al (2016), it is subject to processes such as leaching, volatilization, photodegradation, chemical and microbiological decomposition, surface runoff.…”

“…In this sense, the development of new formulations for controlled release of herbicides that are simultaneously effective in controlling weeds, safe for workers and the environment, is essential (Grillo, 2014). Studies on the encapsulation of herbicide molecules in microparticles, using biodegradable polymers aimed at their controlled release, have been the subject of research in recent years (Silva et al, 2010(Silva et al, , 2011Faria et al, 2016). Among those materials, polymeric microparticles (NPs) for the controlled release of pesticides has shown promising results like as verified by Grillo et al (2012) and Kumar et al (2014).…”

Controlled Release of Herbicides Using Nano-Formulation: A Review

“…[4], a novel pesticide carrier LA-NSM (lauric acid-modified Nitraria seed meal) with controlled release property was prepared through grafting esterification of lauric acid onto Nitraria seed meal substrates [4]. Until now, studies carried out on controlled release of herbicides and other pesticides show that this system only allows for a very simple, effective, safer and slower release of pesticide active ingredient in preference to a quick release based on environmental requirements [33,30].…”