Cuminaldehyde: a potent antifungal agent for managing postharvest blue mold disease in Citrus reticulata Blanco cv. Ponkan.

Cuminaldehyde demonstrates strong antimicrobial properties against several disease-causing organisms. This study investigated its antifungal effectiveness against an imazalil-resistant strain of Penicillium italicum, the pathogen responsible for postharvest blue mold disease in citrus fruits. Cuminaldehyde significantly inhibited the mycelial growth of P. italicum, with both the minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) estimated at 0.5 mL/L. In vivo assays revealed that treatment with 4 × MFC cuminaldehyde in Tween-80 significantly reduced blue mold incidence in Ponkan mandarins inoculated with P. italicum. After 6 days of incubation, the disease incidence in fruits treated with 4 × MFC cuminaldehyde was approximately 72%, compared to 80% in the Prochloraz-treated fruits and 100% in the control group. The antifungal activity was attributed to the activation of oxidative stress, as evidenced by the accumulation of reactive oxygen species, damage to plasma membrane permeability in hyphal cells, and leakage of intracellular components. Additionally, treatment with 4 × MFC cuminaldehyde preserved the quality of the inoculated Ponkan mandarins by day 6. Overall, these findings indicate that cuminaldehyde is a potent antifungal alternative to current chemical fungicides used for controlling postharvest blue mold disease in Ponkan mandarins.