Published online by Cambridge University Press: 05 August 2010
Introduction. Rhizopus stolonifer is thecausal agent of Rhizopus rot disease in various fruit and vegetables.Materials and methods. The effect of chitosan was evaluated invitro on mycelial growth, sporulation, morphological characteristics andgermination of spores of three isolates of R. stolonifer (from peach,papaya and tomato). The effect of chitosan on controlling Rhizopus decayin peach, papaya and tomato fruit in situ in comparison with thesynthetic fungicide dichloran was also studied. Results and discussion. Ourresults showed that the mycelial growth and sporulation of the three isolates weremarkedly inhibited at all tested chitosan concentrations. The highest antifungal indexesand sporulation reduction were observed with chitosan at 2 mg·mL–1. In ourstudy, the morphological characteristics of the spores of R. stolonifershowed different behavior depending on the evaluated isolates. In general, the highesteffect on germination was observed at the chitosan concentration of 2 mg·mL–1.Our results demonstrated that chitosan was effective in reducing the percentage ofinfection and the severity index on peach, papaya and tomato fruit compared with those ofnon-treated control. The chitosan was not more effective than dichloran in reducing thepercentage of infection. The results of the study suggest that chitosan(2 mg·mL–1) is a good alternative for the control ofRhizopus decay on peach, papaya and tomato fruit; it could beconsidered as a potential agent in natural alternatives to control postharvestdiseases.