Application of Thymol Vapors to Control Postharvest Decay Caused by and in Grapefruit.

Two of the major postharvest diseases impacting grapefruit shelf life and marketability in the state of Florida (USA) are stem-end rot (SER) caused by and green mold (GM) caused by . Here, we investigated the in vitro and in vivo efficacy of vapors of thymol, a natural compound found in the essential oil of various plants and the primary constituent of thyme () oil, as a potential solution for the management of GM and SER. Thymol vapors at concentrations lower than 10 mg L significantly inhibited the mycelial growth of both pathogens, causing severe ultrastructural damage to conidia. In in vivo trials, the incidence and lesion area of GM and SER on inoculated grapefruit were significantly reduced after a 5 d exposure to 50 mg L thymol vapors. In addition, the in vitro and in vivo sporulation of was suppressed by thymol. When applied in its vapor phase, thymol had no negative effect on the fruit, neither introducing perceivable off-flavor nor causing additional weight loss. Our findings support the pursuit of further studies on the use of thymol, recognized as safe for human health and the environment, as a promising strategy for grapefruit postharvest disease management.