Effect of essential oil from Asarum heterotropoides Fr.Schmidt var.mandshuricum(Maxim.)Kitag on hypha growth of sixteen plant pathogenic fungi was tested at concentration of 500 μg/mL.The inhibition rates to fourteen plant pathogenic fungi were above 50%,which showed the essential oil had broad-spectrum antifungal activity.According to the toxicity curve of essential oil to Alternaria humicola,the EC50 to mycelium growth and spores germination were 326.86 μg/mL and 406.24 μg/mL respectively.Furthermore,the effect of essential oil on cell membrane potential of A.humicola was tested by the conductivity method.The results showed the action of essential oil was changing osmosis of cell membrane of fungi.
