Chitosan directly inhibited spore germination, germ tube elongation and mycelial growth on A. alternata. These results confirmed other findings on antifungal activity of chitosan against several fungal pathogens including B. cinerea and P. expansum in vitro. Besides its antifungal activity, chitosan also has the potential for inducing defense-related enzymes. However, to the best of our knowledge, there is little information concerning the combined inhibitory effect of chitosan and MeJA in controlling postharvest decay caused by A. alternata in tomato.