Synthesis and antibacterial of carboxymethyl starch-grafted poly(vinyl imidazole) against some plant pathogens.

Poly(N-vinyl imidazole) (PVI) has been grafted onto carboxymethyl starch (CMS) in aqueous solution using potassium persulfate (KPS) as initiator. Reaction parameters that affect grafting efficiency and percentage grafting such as monomer and initiator concentration, the reaction temperature and time were investigated. The grafted products were characterized by FTIR, thermal analysis, SEM photograph and elemental analysis. The antibacterial effects of the carboxymethyl starch-grafted-poly(N-vinylimidazole) (CMS-g-PVI) was examined against two plant pathogens Gram negative bacteria: Xanthomonas perforanss and Xanthomonas oryzae. Generally, upon application of the CMS-g-PVI to the bacterial cells; the mortality rate increased from 45.71 to 59.37% for Xanthomonas perforans and X. oryzae, respectively. While the MIC for most of both bacterial strains were recorded at concentration of 60 μg/mL. The results indicate that CMS-g-PVI has bactericidal properties and can be used for seed treatment to control xanthomonads associated with bacterial leaf spot (BLS).