The objective of the present research was to test the activity of calcium chloride and
lemongrass oil, alone or in combination, against Rhizopus stolonifer on peaches. The inhibitory
effect was evaluated both in vitro and in vivo. Results showed that in vitro pathogen growth
decreased as treatment’s concentration increased, reaching a complete inhibition at 1.5 ml/l and
20 g/l for lemongrass and calcium chloride, respectively. However, taking into account
phytotoxicity phenomena, lower concentrations were tested in vivo. A 70% reduction of both rot
incidence and severity was achieved using lemongrass oil at 1.5 ml/l; whereas, in presence of CaCl2
, the disease reduction was much lower, reaching a maximum at 1.5 g/l of
30 and 59% for incidence and severity, respectively. The combination of the two treatments gave the
best
performance against rot, and the control effect proved to be synergic as far as disease severity
concerns. The observation using scanning electron microscopy (SEM) confirmed the ultra-structure
modification in R. stolonifer after treatment. New strategies are needed to reach the critical goal
of controlling Rhizopus rot of peaches with no fungicide residues on fruit. In this context, the
integration of calcium chloride with
lemongrass essential oil might be promising, although further trials are needed.