Effects of some natural volatile compounds on the pathogenic fungiAlternaria alternata andBotrytis cinerea.

A bioassay system was developed to test the effects of volatile compounds on the growth of hyphae from germinating fungal spores. Volatiles from crushed tomato leaves inhibited hyphal growth of two fungal pathogens,Alternaria alternata andBotrytis cinerea. Aldehydes, including C6 and C9 compounds formed by the lipoxygenase enzyme pathway upon wounding leaves, inhibited growth of both fungal species. Terpene hydrocarbons, 2-carene and limonene, had no significant effect on hyphal growth. The quantities of volatile compounds in the vapor phase of the bioassay system were measured by direct headspace sampling and GC analysis.