Two in vivo trials were carried out in order to evaluate the effect of acetic acid vapor (AA) as an alternative for postharvest control of gray mold (Botrytis cinerea) in 'Itália' grapes. The direct and indirect effect of AA over treated bunches before and after pathogen inoculation was evaluated. In trial 1, grape bunches were inoculated and after 4 h submitted to AA vapors (0.0, 0.25, 0.5, 1.0 or 2.0 mL) in hermetic chambers (200 L), at 25±1 ºC / 70-80 % RH, for 30 min. In trial 2, grape bunches were vaporized or not with AA (1 mL 100 L-1) and after 24, 48, 72 or 96 h, inoculated with B. cinerea. For inoculation, in each bunch (10 per treatment) 10 berries were injured with a ±2 mm deep puncture and sprayed with a spore suspension (±105 conidia mL-1). After treatments, bunches were stored at 25±1 ºC / 80-90 % RH and daily evaluated regarding rot incidence and severity. The in vitro effect of AA vapor on pathogen control was evaluated in order to verify if this agent would directly affect mycelia growth and B. cinerea conidia germination. In the in vivo trials, AA vapor control B. cinerea rot in 'Itália' grape in bunches inoculated before and after treatment with AA. Grapes inoculated 48 h after treatment with AA showed the lowest disease incidence index. In vitro AA has a direct effect on mycelia growth and conidia germination of B. cinerea.
Vitis vinifera L.; gray mold; alternative control
