Selective antifungal activity of chitosan and sulfonated chitosan against postharvest fungus isolated from blueberry.

Two fungal isolates, F12‐20 and F3‐1, were collected from postharvest blueberry in China. By phylogenetic analysis with the nuclear ribosomal internal transcribed spacer region and morphological analyses, they were initially identified as Penicillium and Arthrinium sacchari (A. sacchari). The results showed that water‐soluble chitosan (WCS) and sulfonated chitosan (SCS) could significantly reduce the radial growth of fungal mycelia. The best concentrations were 0.25 and 16 g L–1 for WCS and 0.50 and 64 g L–1 for SCS against Penicillium sp. and A. sacchari, respectively. Importantly, SCS exhibited selective antifungal activity against Botrytis cinerea and A. sacchari. As different species of fungi may respond differently to fungicides, the findings of this study will provide a basis for the development of target‐specific pathogen control and will be useful in designing and implementing fungicide resistance management for control postharvest decay, thus extending the storage life of fresh blueberry. Practical application Experimental results obtained herein are useful for designing and implementing fungicide resistance management for control postharvest decay in blueberry to improve marketable fruit and extend the storage life of fresh blueberries. And sulfonated chitosan can be applied to the target‐specific pathogen control. [ABSTRACT FROM AUTHOR]