Abstract

The antifungal metabolite was purified from a mutant strain of Trichoderma harzianum T-156-co5 by a chromatography procedure. The chemical constituent of the antifungal metabolite was determined by ¹H and ¹³C Nuclear Magnetic Resonance (NMR) spectroscopy. The NMR spectroscopic data showed that the antifungal compound was closely related to isoharziandione. The purified antifungal metabolite at concentrations of 50 and 100 mg L ^-1 was tested for the inhibition of spore germination of Colletotrichum capsici, a causal agent of anthracnose on chili (Capsicum annuum L. var. annuum). The result showed that both concentrations gave high percentages of inhibition, with 100 mg L ^-1 providing the highest efficacy of 83.4% compared with control 2 (sterilized water). Purified antifungal metabolite at 100 mg L ^-1 was also comparable with 100 mg L ^-1 benomyl in controlling anthracnose on detached chili fruits. The treatment with 100 mg L ^-1 gave the highest disease control efficacy of 89.9% compared with control 2, whereas 88.5% disease inhibition was observed in chili fruits treated with 100 mg L ^-1 benomyl. Control 1 (2% methanol) treatment showed only 6.4% disease inhibition.