Studies on the Varieties and Pathogenic Ability of the Pathogenic Fungi of Chinese Chestnut Seed in Different Production Areas of China

One hundred forty six isolates were obtained from samples of Chinese chestnut (Castanea mollissima) collected from eight different production areas in Beijing, Hebei, Shandong, Anhui, Jiangxi, Hubei, Hunan, Guangxi. They were designated as 11 genera, and the pathogenic ability of 6 popularly distributed genera of 11 was studied through reinoculation experiment. The results showed that the natural fungal flora in chestnut seeds were different among different production areas. The most popularly distributed fungi are Penicillium sp., Fusarium sp., Mucor sp., Dothiorella sp., Pestalotiopsis sp., Phomopsis sp. and Rhizoctonia sp. Reinoculation experiment of several predominant fungi reflected that the pathogenic ability among different fungi has great diversity. At the same condition, the degree of a disease caused by Rhizoctoria sp. was the most deeply and the pathogenic ability was the strongest while the pathogenic ability of Penicillium sp. was the weakest among these 6 predominant fungi. The effect on the rot of the flesh of chestnut seeds was very different in different methods of inoculation. The incidence of a disease inoculated the flesh was higher than any other ways of inoculation and reached more than 90%. But the flesh did not rot by inoculating the peel of chestnut seeds, or rolling the whole sound seeds in the suspended solution of spores. From the reinoculation experiment by using a single fungus we can see that the characteristic of rotted spot caused by different pathogen microbe has great diversity.