Control of postharvest grey mould (Botrytis cinerea Per.: Fr.) on strawberries by glucosinolate-derived allyl-isothiocyanate treatments

The vapours of allyl-isothiocyanate (AITC) were evaluated in in vitro and in vivo trials against Botrytiscinerea, a severe pathogen of strawberries. In in vitro trials AITC activity was assayed on conidial germi-nation and mycelial growth of the fungus. The mycelium appeared less sensitive to AITC than conidia(EC50values of 1.35 mg L−1and 0.62 mg L−1, respectively). In addition, AITC had a fungistatic effect againstthe pathogen, since the values of EC50, for both parameters, increased by around 30% after AITC removal.In in vivo trials, ‘Tecla’ and ‘Monterey’ strawberries (spring-bearing and day-neutral cultivars, respec-tively) obtained from organic production and naturally infected by B. Cinerea, were exposed for 4 h in anatmosphere enriched by pure AITC or derived from defatted seed meals of Brassica carinata (0.1 mg L−1,in a 0.1 m3treatment cabinet). After 2 days at 0◦C and another 3–4 days at 20◦C, the fruit were evalu-ated for grey mould infections. The AITC treatment reduced the decay caused by the pathogen by over47.4% up to 91.5%, significantly different from the untreated fruit. No significant differences were foundbetween synthetic and glucosinolate-derived AITC. Residue analysis performed on fruit at the end ofstorage (7 d after treatment) showed values lower than 1 mg kg−1. Total phenolic content and antioxi-dant capacity estimated in treated and untreated strawberries showed no significant difference betweencontrol and AITC treated fruit. Our results show it is possible to reduce the incidence of postharvest greymould on strawberries with a treatment of AITC (0.1 mg L−1) for 4 h, opening a potential application ofbiofumigation in the postharvest control of B. cinerea in strawberry.