ABSTRACT
Study on the symptoms of the diseases on infected Atractylodes macrocephala Koidz. in Ha Noi, Hung Yen and Lao Cai province. Results: Atractylodes macrocephala Koidz. was infected with harmful disease such as root ulcer caused by Rhizoctonia solani, tuber stink caused by Fusarium solani, brown spot and leaf burn due to Pestalozia sp. The fungus Sclerotium rolfssi isolated from A.macrocephala grew best on PGA medium with the most sclerotia produced at pH=6, was similar with those isolated from tomatoes. Trichoderma viride, a biological product can inhibit the growth of S.rolfsii with 85.49% efficacy and can be applied to control this fungus in the field. Chemical material Ridomil 0.05% can annihilate Sclerotium rolfsii fungus with 100% efficacy after 3 cultured days