Study on pests and diseases of some important medicinal plants in the winter-spring crop 2003 - 2004 at Hanoi Center of Research and Processing of Medicinal Plants

Forty-three species of insects and mites belonging to 21 families and four orders have been found associated with seven species of medicinal plants (Angelica dahurica Benth. et, Atractyloides macrocephala Koidz, Crinum latifolium L., Datura metel L., Phylanthus urinaria L., Geranium nepalense Kudo, Silybum marianum L.) at the Research Center for Medicinal Plants - Hanoi in the winter-spring crop 2003-2004. In addition, 22 species of pathogens including fungi, bacteria and viruses were also recognized. Some unknown pathogens remained to be identified. The density and damage caused by some main insects and pathogens such Wi Spodoptera litura Farb.; Argyrogramma agnata Standinger; Homona coffearia Nietnex, Noctuidae;Erwinia carolovora; Alternaria sp. have been investigated. Initial study on the chemical control method has been conducted. Further investigation is need in 2004-2005 seasons to determine other causal agents and effective control for the studied medicinal plants

Sclerotium rolfsii associated with Atractyloides macrocephala Loidz. and initial study on some control measures

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

Soil analysis in some medicinal plant growing areas

Soil samples were collected in the provinces of Hai Duong and Thanh Hoa, and in Ha Noi, Da Lat and Sapa cities. Each sample was taken from 9 spots of soil situated on 2 diagonals, that were mixed together. The chemical composition of the soil varied widely in different ecological areas. All the samples of soil showed light acid reaction, while those taken from Sapa (province of Lao Cai) were the most acid. Ha Noi soil samples were neutral. Almost soil samples were poor in total N, P and K, except that of Sapa, which was rich in N, while samples taken from Ha Noi and Thanh Hoa were the poorest. The total amount of P and K varied from poor to medium.