In vitro activity of 6-pentyl-α-pyrone, a metabolite of Trichoderma harzianum, in the inhibition of Rhizoctonia solani and Fusarium oxysporum f. sp. lycopersici

The compound 6-pentyl-α-pyrone [6-p-p]produced by Trichoderma harzianum IMI 288012 was used in plate tests against Rhizoctonia solani and Fusarium oxysporum f. sp. lycopersici . The addition of 0·3 mg ml −1 6-p-p to agar medium caused a 69·6% reduction of growth of Rhizoctonia solani and 31·7% reduction of growth of Fusarium oxysporum f. sp. lycopersici after 2 d. When used in spore germination tests 0·45 mg ml −1 6-p-p was found to inhibit completely the germination of Fusarium spores. A strong relationship was found between the production of the pyrone by T. harzianum and the antagonistic ability of this fungus in vitro .