Screening of Chinese herbs for the fungitoxicity against Phytophthora infestans

Plant extracts of 88 species from 44 families of plants were diluted to 500 times, and mixed with sporangia suspension of P. infestans , then the sporangia suspensions were put into 10℃ incubator for 3 hours. The result is as follows: 31 species were completely inhibitory, 46 species were strongly or moderately inhibitory and 11 were little inhibitory to sporangia indirect germination of P. infestans . And among 83 species in 43 families of plants tested, mother extracts from 32 species were completely inhibitory, 24 were strongly inhibitory and 27 were weakly or even no inhibitory to mycelial growth of P. infestans at 200 times. There are also 19 mother extracts were not only completely inhibitory to germination of sporangia but also completely inhibitory to mycelial growth of P. infestans .