Development of controlled release formulations of thiram employing amphiphilic polymers and their bioefficacy evaluation in seed quality enhancement studies

Abstract

Controlled release formulations of Thiram (Dimethylcarbamothioylsulfanyl-N,N-dimethylcarbamodithioate), a contact fungicide, have been prepared using laboratory synthesized poly(ethylene glycol) (PEG) based functionalized amphiphilic copolymers. The kinetics of thiram from developed controlled release (CR) formulations were studied in comparison with that of the commercially available 75 WS. Release from the commercial formulation was faster than with the developed CR formulations. Maximum amount of thiram was released on 35th day for PEG-2000 4d, 28th day for PEG-1500 4c, 21st day for PEG-1000 4b and 15th day for PEG-600 4a in comparison to commercial formulation (7th day). The diffusion exponent (n) of thiram in water ranged from 0.356 to 0.545 in the tested formulations. The half-release (t(1/2)) values ranged between 14.78 to 22.1 days, and the Period of Optimum Availability (POA) of thiram ranged from 7.79 to 25.15 days. An effort has also been made to identify the suitable polymers that could reduce the seed deterioration during storage and also act as an effective carrier of fungicide thiram. The results demonstrate that the seeds coated with the different formulations deteriorated at a slower pace as manifested in high germination percentage over control. Apart from the fungicidal effect of thiram, the polymers acted as barriers to moisture reducing the rate of seed deterioration and checked the degradation of thiram. The CR formulation 4d, with PEG 2000, was found to be most effective as seed coat.

Post‐harvest management control of Ectomyelois ceratoniae (Zeller) (Lepidoptera: Pyralidae): new insights through essential oil encapsulation in cyclodextrin

“…There have been various achievements regarding the application of encapsulated essential oils or their components for the management of storage insect pests. In this respect, Kaushik et al . pointed out that encapsulation of Curcuma longa (L.) (Zingiberaceae) essential oil in alginate gel gave best control towards the cowpea weevil Callosobruchus maculatus (Fabricius) (Coleoptera: Bruchidae).…”

The framework of nanopesticides: a paradigm in biodiversity

“…The exponent value gives the type of release mechanism: (a) n o 0.43 means that the mechanism is Fickian diffusion, (b) n 4 0.85 means that release is regulated by the process of relaxation and (c) 0.43 o n o 0.85 reflects anomalous characteristics with the kinetics of non-Fickian release and an amalgamation of the relaxation and diffusion of polymeric chains. 99,100 Some other linear models, such as first and second-order kinetic models, have also been employed. The aforementioned results demonstrated that the release of pesticide active ingredients is influenced by diffusion via the polymeric matrix, the surface desorption and the degradation of the polymeric structure.…”

Nanopesticide: Current Status and Future Possibilities

“…Nano-formulation were also developed to improve efficiency, stability and reduction of effective pesticide concentration, like nanoformulation of pyridalyl [46,47], insecticide coated liposome [48], neem oil [49], garlic essential oil [50], Artemisia arborescens essential oil [51], imidacloprid [52], thiamethoxam [53], carbofuran [54], thiram [55] and β-cyfluthrin [15], carbofuran [56], mancozeb [57], atrazine and simazine [41], oilcore silica-shell nanocapsule for fipronil [58], lansiumamide B [59].…”