Lemon postharvest losses are mainly due to the presence of fungal diseases. Current postharvest decay strategies rely on synthetic chemical fungicides; however, consumers are demanding that fruit is free of any chemical residue. The use of new natural alternatives, including essential oils, is emerging due to their potential antimicrobial activity. Therefore, the aim of this work is the elucidation of the effect of carvacrol, eugenol, and thymol, individually and in combination, applied in preharvest. Three different concentrations (100, 500, and 1000 µL/mL) of carvacrol, eugenol, and thymol were individually applied and in combination in ‘Fino’ and ‘Verna’ lemon cultivars. The fungal incidence (mainly Penicillium digitatum and P. italicum) was evaluated weekly for 35 days. Moreover, the main different quality parameters (weight loss, firmness, colour, total soluble solids, titratable acidity, and total phenolic content) of lemons were evaluated at harvest and after 35 days of cold storage. The results showed that carvacrol at the lowest concentration (100 µL/L) provided the lowest fungal incidence with a non-negative effect on the lemon quality parameters during storage, while the highest concentrations and the combination of essential oils resulted in the opposite effect. Therefore, carvacrol applied at 100 µL/L in preharvest could be an eco-friendly alternative to the current fungicides to control lemon decay, while maintaining their optimal quality.

Fertigation is a technique of injecting fertilizers along the irrigation lines, allowing a precise control of the moisture and the application. Nowadays, the main fertilizers used are nitrogen and potassium. Usually, an excess of fertigation is applied to achieve an early harvest of the lemon fruit. However, there is no literature available regarding the effects of excess fertigation on lemon fruit quality and antioxidant systems at harvest and during cold storage. Therefore, the present study aims to investigate these effects. This experiment was developed by comparing two plots: the first one with standard fertigation (SF) and the second one with intensive fertigation (IF). The yield per tree in the early harvest was higher in the IF than the SF plot; however, total yield was similar under both fertigation strategies. Lemons from the SF plot maintained higher total phenolic content and total antioxidant activity compared with lemons from the IF plot. In addition, firmness, total soluble solids and titratable acidity were also higher in SF lemons. Furthermore, weight loss, ethylene production, colour (parameter a*) and decay incidence were reduced in lemon fruits from the SF plot. Early lemons harvested from the standard fertigation plot showed high physicochemical quality and antioxidant properties, reducing lemon fruit decay during cold storage and providing high-quality fruits to consumers.