Inhibition of Amphiphilic N-Alkyl-O-carboxymethyl Chitosan Derivatives on Alternaria macrospora

Abstract EN

Cotton leaf spot (Alternaria macrospora) is a widespread disease that occurs in the main cotton-producing area of China.

In managing this disease, a novel chitosan-based biopesticide, an amphiphilic N-alkyl-O-carboxymethyl chitosan derivative, was prepared.

The product was selected from variations of chitosan with different molecular structures, which were obtained via a two-step reaction.

First, carboxymethyl chitosans with varying molecular sizes were obtained by etherification with chloroacetic acid; then the carboxymethyl chitosan was alkylated with C4–C12 fatty aldehyde through a Schiff-base reaction.

This procedure resulted in derivatives of amphiphilic N-alkyl-O-carboxymethyl chitosan, which showed strong antifungal activities against A.

macrospora, and the efficacy was determined by its molecular structure.