Enhancement of the performance of Candida saitoana by the addition of glycolchitosan for the control of postharvest decay of apple and citrus fruit

Abstract

At a concentration of 0.025% (w/v) chitosan-chloride inhibited spore germination of Botrytis cinerea, Penicillium expansum, and Candida saitoana. In contrast, at 0.5% (w/v) glycolchitosan inhibited spore germination of B. cinerea and P. expansum, but not the growth of C. saitoana in vitro or in apple wounds. The combination of C. saitoana with 0.2% glycolchitosan was more effective in controlling gray and blue mold of apple caused by B. cinerea and P. expansum, respectively, and green mold of oranges and lemons caused by P. digitatum than C. saitoana or 0.2% glycolchitosan alone. The level of control was similar to that obtained with the fungicide imazalil on oranges and lemons. C. saitoana in combination with 0.2% glycolchitosan reduced green mold incidence equally on light green and yellow lemons, while C. saitoana was more effective on light green lemons than on yellow lemons. When applied as a pretreatment, sodium carbonate enhanced the efficacy of all treatments tested against green mold with the greatest effect on light green lemons. Of the treatments tested, pretreatment with sodium carbonate followed by the combination of C. saitoana with 0.2% glycolchitosan was the most effective in controlling green mold of both light green and yellow lemons.