The present work aimed to evaluate capability of certain acids and oils as postharvest treatments
to induce resistance of “Kiett” mango fruits against Colletotrichum gloeosporioides in vitro and in vivo.
Therefore, essential oils like Thyme and Cinnamon, and certain acids such as Salicylic and Boric have been
tested to evaluate their effects on fruit deterioration of mango post harvest quality. Results indicated that Thyme
oil showed the highest efficacy in inhibiting fungal growth followed by Cinnamon oil giving inhibition
percentage of 77.8 and 61% for both oils respectively, at their concentrations of 10000 ppm while both Salicylic
and Boric acids caused complete mycelial growth inhibition at their concentration of 500, 3000ppm,
respectively. On the other side, decay incidence of mango fruits treated with Thyme oil or Cinnamon oil were
significantly than the other treatments either naturally or artificially infected with fungi. The lowest values of
weight loss percentage were resulted from Thyme oil treatment of naturally infected fruits, while for artificially
infected fruits, the Cinnamon oil treatment caused the lowest ones in two seasons. Moreover, postharvest
treatments with Thyme oil or Cinnamon oil of mango fruits either naturally or artificially infected with fungi
significantly decreased change rate of fruit colour that means delayed fruit ripening in comparison with the other
treatments and control fruits. In addition, these treatments significantly decreased the deterioration rate of fruit
contents of total soluble solids (TSS), titratable acidity (TA), total phenol contents (TPC) and polyphenol
oxidase (PPO) compared with the other treatments and control. In conclusion, it could be concluded that
postharvest treatments of mango fruits with Thyme or Cinnamon oils at 10000 ppm can be an effective method
in order to increase “Kiett” mango fruit storability and keep fruit quality during storage.