Efficacy of essential oil vapours in reducing postharvest rots of nectarines and effect on the fruit microbiome

Essential oils (EOs) could be a promising alternative to synthetic fungicides to reduce postharvest decay. This work investigated the effectiveness of EO biofumigation using slow release diffusers to control storage rots of nectarines, while also evaluatin g their effect on the fruit quality and microbiome. An in vivo screening trial was performed by treating nectarines, inoculated with Monilinia fructicola , with basil, fennel, lemon, oregano and thyme EOs. Fennel, lemon and basil EO showed the greatest inhi bition activity after storage and were selected to be tested in efficacy trials using naturally contaminated nectarines. All treatments showed a significant rot reduction compared with the untreated control after 28 days of storage. Moreover, no evident ph ytotoxic effects were observed. EO vapours did not affect the overall fruit quality but showed a positive effect in reducing firmness loss. To determine the main compounds that might be responsible for antifungal activity, EO composition was analysed using GC MS. Microbiome analysis showed that the abundance of some fungal genera was modified. Treatments were able to reduce the abundance of Monilinia spp., however basil EO seems to favour the presence of Penicillium spp. during shelf life. Results provide new insights for the development of sustainable strategies for postharvest disease management.