| Abstract
| - Preparation and characterization of microencapsulated tebuconazole, its release kinetics in water,and the bioefficacy of these formulations in controlling wheat rust in spring wheat is described herein.Controlled-release (CR) formulations based on matrix microparticles were prepared by the oil-in-water emulsion process. Polymer-based matrix was prepared from poly(methyl methacrylate) (PMMA)and poly(styrene-co-maleic anhydride) (PSMA). Modification of the matrix was achieved by the useof different low molecular weight or polymeric additives. These additives were found to lower theglass transition temperature of the matrix and enhance the release rate of tebuconazole in water,under infinite sink conditions. Release of tebuconazole from matrix microparticles was found to bediffusion controlled. CR formulations were found to be very efficacious in controlling wheat rust. Soil-applied CR formulations prepared from a PMMA or PSMA matrix, modified with poly(vinyl acetate),were as effective in controlling wheat rust (Puccinia recondita) as foliar-applied tebuconazole, Raxil,from Bayer AG. Results suggest that CR formulations with a systemic fungicide, such as tebuconazole,applied as either a soil or seed treatment, may provide control of foliar diseases, possibly eliminatingor reducing the need for traditional foliar applications. Keywords: Tebuconazole; controlled release; microparticles
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