Efficacy of biofumigation with essential oils in the control of postharvest rots on nectarines.

The most common postharvest pathogens on nectarines are Monilinia fructicola and M. laxa, followed by minor pathogens. The efficacy of five essential oils (EOs) was evaluated against postharvest rots on nectarines. Biofumigation of EOs of red thyme, fennel, basil, oregano, and lemon at a concentration of 2% were evaluated to control brown rot. Disease incidence was evaluated after 14 days of storage at 1°C and after further 7 days shelf-life at 20°C. At the end of storage, nectarines treated with fennel EO showed a significant reduction in rots, whereas the other EOs were not compared to the inoculated control. Isolations from fruit rots showed a prevalence of Monilinia spp., followed by Botrytis cinerea at the end of storage, and of Monilinia spp., with minor occurrence of Penicillium spp., Botrytis spp., and Rhizopus spp. at the end of shelf-life. In the second trial, biofumigation was realized with EOs of fennel, basil, and lemon at the same concentration. Disease incidence was evaluated after a longer storage (28 days) at 1°C and after further 5 days shelf-life at 20°C. At the end of storage, nectarines treated with EOs showed a significant reduction in rots, which were caused by Monilinia spp. At the end of shelflife, the agents of rots were Monilinia spp., Penicillium spp., Botrytis spp., Alternaria spp., and Rhizopus spp.. In the second trial, fruit quality and microbiome composition were analysed at harvest, after 28 days of storage, and after 5 days of shelf-life. The firmness in the treated fruits with EOs was higher compared to the untreated ones. Treatments with biofumigation with EOs are promising tools for the control of postharvest rots. This work was conducted within the framework of the PRIMA StopMedWaste project, which is funded by PRIMA, a programme supported by the European Union.