Antifungal vapour-phase activity of allyl-isothiocyanate against Penicillium expansum on pears

摘要

The fungitoxicity of ally-isothiocyanate (AITC) vapour against Penicillium ecpansum, the causal agent of blue mould on pears (cvs Conference and Kaiser), was evaluated. The best control of blue mould was obtained by exposing fruits for 24h in a 5 mg L~(-1) AITC-enriched atmosphere, the extent of control depending on the inoculum density. Lesion diameter was inversely related to AITC concentration. In treated fruits the percentage of infected wounds increased with conidial concentration, with fewer than 20% affected at 1 X 10~3 conidia mL~(-1) to almost 80% at 1 X 10~6 condidia mL~(-1). In comparison, >98% of wounds were infected in untreated fruits irrespective of conidial concentration. AITC treatments were effective up to 24h after inoculation for Conference and 48h for Kaiser. AITC treatments also controlled a thiabendazole-resistant strain of P.expansum, reducing the incidence of blue mould buy 90% in both cultivars. The use of AITC produced from pure signigrin or from Brassica juncea defatted meal may be an economically viable alternative to synthetic fungicides against P.expansum.