SUGAR ANALOGS AS POTENTIAL FUNGICIDES FOR POSTHARVEST PATHOGENS OF APPLE AND PEACH

One-percent solutions of 2-deoxy-D-glucose, D-mannose, raffinose, L-sorbose, and 2-deoxy-D-ribose were tested as potential fungicides in apple and peach fruit wounds inoculated with Botrytis cinerea and Penicillium expansum in apple and Monilinia fructicola in peach. Among the sugar analogs tested, only 2-deoxy-D-glucose was effective in controlling decay in inoculated apple and peach fruit. A slight reduction in lesion diameter was detected with L-sorbose and D-mannose. Radial growth of B. cinerea, P. expansum, M. fructicola, and Rhizopus stolonifer was completely inhibited in vitro when 2-deoxy-D-glucose was incorporated into a potato-dextrose agar medium at a 1.0% concentration. Severe alterations in fungal growth were also observed including excessive branching, shortening of the hyphal segments, and hyphal swelling. The sugar analog, 2-deoxy-D-glucose, shows promise as a treatment for postharvest diseases. Effective formulations that are safe to humans must be developed before this technology can be used commercially.