Antifungal Activity of Citrus Essential Oil in Controlling Sour Rot in Tahiti Acid Lime Fruits

Sour rot, caused by Geotrichum citri-aurantii, is a significant post-harvest disease in citrus, resulting in economic losses due to the lack of effective fungicides. This study investigates the antifungal activity of essential oils from Late IAC 585 willowleaf and Pera IAC sweet orange in controlling sour rot in Tahiti acid lime fruits. Essential oils were extracted via hydrodistillation and tested in vitro and in vivo. In vitro, assays evaluated mycelial growth inhibition at concentrations ranging from 2 to 32 µl ml⁻¹. In vivo trials involved preventive and curative treatments on artificially inoculated fruits stored at 25°C ± 2. Results showed that Pera IAC sweet orange oil, at 32 µl ml⁻¹, reduced disease severity by 96% in curative treatments. In contrast, Late mandarin oil demonstrated moderate inhibition (44%) at the highest concentration in vitro. The oils did not affect key fruit quality parameters such as juice yield and total soluble solids. These findings suggest that citrus essential oils could be natural alternatives to synthetic fungicides for post-harvest sour rot management, combining effectiveness with maintaining fruit quality. Further research is needed to explore the mechanisms of action and commercial application potential.