Effect of Some Postharvest Treatments on Guava Fruit Rots Caused by Pestalotia neglecta and Quality and Storability During Cold Storage

Guava fruit rots of Etmani’ guava is a major serious decay during cold storage in Egypt and world. Infection of guava fruits Pestalotia neglecta mainly attacks the unripe fruits. It reduces fruits quality and marketability of guava during storage. The effect of safe fungicide alternatives (some essential oils and their active ingredients such as clove oil, thyme oil, lavender oil, and its combinations) on growth of Pestalotia neglecta were studied during this study. This study was investigated at different concentrations ranged from 0.0125% to 1% amended in PDA in vitro. Eugenol+geraniol+thymol formula) at 1-0.0125% completely suppressed the growth of the isolate of Pestalotia neglecta. These some essential oils and their active ingredients formula at 1%, were used as postharvest treatment during seasons 2023 and 2024. These some essential oils were adopted at 1% on naturally infected or artificially inoculated fruits after harvest during season 2023/2024. Clove oil, thyme oil, lavender oil, mixed three oils and active ingredient formula were the most effective treatments to control fruits rot disease on guava during cold storage at 8oC and 90-95% RH for 3 weeks. Also, all coating treatments had a significant effect on delaying changes of fruit weight loss percentage, color values (L* and h°), hardness, TSS, acidity, and activities of polyphenol oxidase (PPO), peroxidase (POD) and catalase (CAT), especially coating with Clove oil and mixed three oils (clove oil+ thyme oil+ lavender oil). Therefore, it could be recommended that coating guava fruits by clove oil and mixed three oils to improve its quality and storability during cold storage.