Study On Pathogen And Biologic Characteristics Of The Rot Roots Disease Of Poplar And The Relation Between The Disease And Factors Of Environment

The article summarize the latest study on the disease of root of Poplar, the classic systems of Fusarium and the relation between the disease and factors of environment, and study concretely a new disease of Poplar (rot roots disease of Poplar) which occurs on the north of Jiangsu province recently. The results are as follows. 1. The area of the disease and the important symptoms of the disease Reportedly, the rot roots disease of Poplar occurs on a large-scale area of the north of Jiangsu province mostly. The important symptoms of infected seedling of Poplar as follows: ①The disease harms the 1 to 3 years old seedlings mostly, the infected seedlings'root grow black and rot, many black spots on the twigs, some black spots link strip, and the buds dead for lost water. ②The cuttings rot and seedlings productivity descends. 2. The isolation, inoculation and filtration of pathogenic and pathogenicity test Through isolating fungus, inoculation and pathogenicity test, the DCF-4 and DCF-8 fungus pathogenicity are stronger than the others, they are identified to the pathogenic fungus belongs to which kind fungus and name the new disease. 3 Identification of pathogenic fungus of rot roots disease of Poplar Through observating and mensurating the growth speed of colony, the color, texture and core of the colony, the characteristics of configuration, the sexual phase, the producing cell, the pathogenic fungus is identified to belong to Discolor group and Fusarium heterosporum with the Booth system. 4. The influence of environment factors to pathogen of Fusarium ①The fungus grows rapidly cultivating from 24 to 26℃, and growth stop at 4 and 40℃. The large conidia can germinate from 15 to 35℃moderate, and can not germinate above 40℃and below 4℃. ②The fungus can not grow at pH 2.2 and strong alkalescence, and grow optimum at pH 8.0; The spore can germinate pH from 5.0 to 10.0, pH 8.0-9.0 optimum. ③Light have no much effect on the growth of fungus mycelium and spore germination. ④The pathogenicity is similar at kinds humidity above 90%, about 80%. ⑤Fungus mycelium and spore endure low temperature well, but the endurance to high temperature are not enough. 5. Mensurating and analyzing the physics and chemic index of the soil, and acquiring the microbe totality and fusarium quantity in the soil. 6. Correlation analysis and prominence test and regress analysis By correlation analysis and prominence test, the results shows as follows: the relation of the disease occurrence with the pH, the microbe totality and fusarium quantity in the soil is very obvious, with the water content of soil, organic compound content, total nitrogen content, total phosphorus and effective phosphorus content, effective kalium content is not obvious. As the same time, by regress analysis, establishing the regress equations of one power linear multivariable, the variables with the microbe totality and fusarium quantity in the soil and the independent variables with all of the soil physic and chemic characters. By prominence test, the linear relation is not obvious.