Evaluation of the Antifungal Activity of Aqueous Extracts of Corrigiola telephiifolia and Marrubium vulgare against Major Post-Harvest Citrus Diseases

Citrus fruits are highly susceptible to post-harvest diseases such as green rot (Penicillium digitatum), blue rot (P. italicum), and sour rot (Geotrichum citri-aurantii), causing significant economic losses. Due to the risks associated with synthetic fungicides and the emergence of resistant strains, natural alternatives are needed. This study evaluated the antifungal activity of aqueous extracts of Corrigiola telephiifolia and Marrubium vulgare. In vitro tests were conducted using PDA medium with extract concentrations of 12.5–100 mg/mL and in vivo assays were performed on artificially wounded oranges with the same extract concentrations. In vitro tests showed strong inhibition of mycelial growth and spore germination, with C. telephiifolia reducing pathogen growth by over 70–89%. In vivo assays confirmed its effectiveness, completely preventing green rot at 12.5 mg/mL and significantly reducing sour rot. Phytochemical analysis revealed high levels of polyphenols and flavonoids in C. telephiifolia. These findings suggest that aqueous extracts of C. telephiifolia are a safe and sustainable alternative to synthetic fungicides for managing post-harvest citrus diseases.