A maize plant (Zea mays) planted in a test tube was found to inhibit the growth of the soil-borne plant pathogen, Fusarium oxysporum f. sp. melongenae. The antifungal compounds, 6-methoxybenzoxazolinone and 6,7-dimethoxybenzoxazolinone, were isolated from an ethanol extract of Zea mays roots, and (6R)-7,8-dihydro-3-oxo-alpha-ionone and (6R,9R)-7,8-dihydro-3-oxo-alpha-ionol were isolated from the root exudate.