ABSTRACT The aim of this study was to test the hypothesis that lemongrass and thyme essential oils (EOs) reduce Botrytis cinerea development and control gray mold in ‘Italia’ grapes. The fungitoxicity evaluation was performed by EOs direct contact with the pathogen, in culture medium, and by exposure to the EOs volatile phase. Individualized rachis berries were inoculated by subcuticular injection of a conidia suspension and after 4 hours sprayed with the EOs of lemongrass and thyme (100 to 1,000 mg·L-1), or oils blend (500 mg·L-1 thyme + 100 mg·L-1 lemongrass), and then stored at 25 °C / 75% relative humidity. To verify the possibility that the EOs protect the fruit against B. cinerea, the berries were sprayed with 400 mg·L-1 of each EOs or with the blend (200 mg·L-1 thyme + 200 mg·L-1 lemongrass), and after 24 hours inoculated with B. cinerea. On clusters, thyme (800 mg·L-1) and the blend (500 mg·L-1 thyme + 100 mg·L-1 lemongrass) were sprayed 4 hours after inoculation and then stored at 25 and 1 °C. The disease incidence and severity were analyzed, as well as the fruit quality attributes. EOs had antimicrobial effect, in-vitro, incorporated into the culture medium or by volatilization against B. cinerea. On detached berries, the thyme and oil blend reduced the gray mold severity when inoculated 4 hours before spraying. In clusters, thyme at 800 mg·L-1 significantly reduced the gray mold development only in fruits kept at 1 °C, without impairing the clusters quality, which could be an alternative for the disease management in postharvest.

ABSTRACT Nitric oxide application has been seen as a promising technique to extend the postharvest life of various fresh fruits and vegetables. This is the first work involving the spray application of nitric oxide donor S-nitrosoglutathione (GSNO) on Golden papaya. Considering that results are very distinct depending on the type of the nitric oxide donor, the form of application, the concentration used and the species studied, the application must be adapted to each necessity. The aim of this study was to relate the application of GSNO, spray applied at 10, 100, 1,000 ?M, with the physiological, physical-chemical, and biochemical changes of Golden papaya, in the first 72 h of ripening. Control fruit was sprayed with distilled water. GSNO application did not interfere on color and chlorophyll fluorescence of the peel, on soluble solids, titratable acidity, lipid peroxidation, and in the level of S-nitrosothiols. Control fruit and 10-?M GSNO sprayed showed lower respiration. After 72 h of ripening at 25°C, all fruits showed an increase in ethylene biosynthesis, except for those treated with 10 ?M GSNO. Papaya sprayed with 10-?M GSNO showed the highest pulp firmness and 52% less weight loss when compared to control fruit. GSNO was also responsible for increasing the ascorbic acid in papayas, besides showing an increase in total antioxidant activity production. The results indicated that the application of 10 ?M of GSNO by spray can potentially preserve the quality characteristics of Golden papaya, mainly due to the lower ethylene production, the delay in the firmness loss, and the less weight loss.