Effect of Preharvest Application of Sodium Benzoate and Potassium Sorbate on Fungal Decay Incidence and Postharvest Quality of Cold-Stored Fino Lemon Fruit

The Citrus limon (L.) Burm. f. industry suffers significant losses due to fungal diseases. Therefore, this study aimed to evaluate the effectiveness of sodium benzoate (SB) and potassium sorbate (PS) on the incidence of fungal decay and fruit quality when used as preharvest treatments on Fino lemon trees over two consecutive seasons (2021–2023). Lower concentrations of SB and PS (0.1% and 0.5%) applied in one or two treatments successfully controlled fungal decay. On average, SB achieved a greater reduction in decay, ranging from 45% to 60%, compared to PS’s reduction of 25% to 50%. This approach minimised the negative impact on lemon fruit quality, in contrast to the highest doses (more than 1%) and the greatest number of applications (more than three times), which increased lemon susceptibility to decay. Furthermore, lemons treated with 0.5% SB twice enhanced antioxidant systems, showing a 35% increase in total phenolic content in the flavedo at harvest compared to the control. Consequently, the application of 0.5% SB twice at preharvest emerges as a promising and potential alternative to conventional fungicides for effective fungal decay control and maintenance of acceptable lemon quality traits during cold storage.