抄録
Hinokitiol, citral and allylisothiocyanate, which are chemicals of plant extracts, were investigated for their effectiveness as antifungal agents against the genera Saprolegnia, Aphanomyces and Achlya. The minimum inhibitory concentrations (MICs) of these chemicals were 12.5μg/ml of hinokitiol against all fungal isolates, and 100.0-200.0μg/ml of citral and 50.0-100.0μg/ml of allylisothiocyanate were appeared to inhibit the growth of Saprolegnia and Aphanomyces, but not Achlya. Among these chemicals, 100.0μg/ml of hinokitiol was the most effective agent to inhibit the hyphal growth of S. parasitica ATCC 90213 and Aphanomyces spp. but not of S. diclina ATCC 90215 and Achlya. Hinokitiol also inhibited at 100.0μg/ml the zoospore germination of Saprolegnia spp., whereas 12.5-25.0μg/ml of hinokitiol inhibited the zoospore germination of Aphanomyces spp.(but not Achlya). Treatment with a higher concentration of citral (800.0μg/ml) had an effectiveness of inhibiting the hyphal growth of all fungal isolates but the zoospores of all isolated strains showed higher sensitivity to citral (200.0-400.0μg/ml) than their vegetative stages did. The treatment with 100.0-400.0μg/ml of allylisothiocyanate was found to inhibit the vegetative growth of all fungal isolates except Achlya. On the other hand, the zoospores of all isolates showed higher sensitivity to allylisothiocyanate (200.0-400.0μg/ml) than their vegetative stages did.
