白菜根肿病菌致病性因素研究

Study on Pathogenic Factors of Cabbage Root Swelling

通过对2002年至2004年白菜根肿病主要影响因素研究,结果表明,土壤含水量为20%、30%、40%、50%、60%、70%、80%时,白菜根肿病病情指数分别为0,1.5,10.5,28.6,26.9,19.8,2.9。对病田土壤中根肿病菌休眠孢子囊垂直分布测定,结果为0 cm土层平均含菌量为0.49×106～208.27×106个,10 cm土层为83.85×106～1400.15×106个,20 cm土层为5.1×102～28.7×102个,病田不同土层休眠孢子囊平均含量10 cm>0 cm>20 cm。用0、10、20 cm带菌土壤接种白菜,其根肿病病情指数分别为30.7,25.8,20.0,带菌烘干土样接种未发病。土壤酸碱度与田间根肿病发生有密切关系,pH值5.6～5.97,病株率为100%;pH值6.9～7.59,病株率45.68%～62.96%。病田晒垡60、40、20 d后接种白菜和甘蓝,其病情指数分别为0.47,4.4,38.2和0.2,1.2,24.8。对病根组织泡水和日晒5、10、15 d后接种白菜,其病株率分别为55.2%、79.2%、89.6%和85.7%、100%、100%;新鲜病根接种病株率为84.9%;无病土未发病。

Based on study of the main factors of Plasmodiophora brassicae in 2002-2004,the results showed：（ⅰ） When the soil moisture were 20 %,30 %,40 %,50 %,60 %,70 % and 80 %,the cabbage disease index were 0,1.5,10.5,28.6,26.9,19.8 and 2.9,respectively.（ⅱ）The vertical distribution of dormant sprores in the field were measured,the results showed that the numbers of dormant spores were 0.49×106-208.27×106,83.85×106-1400.15×106,5.1×102-28.7×102 in the soil layer of 0,10 and 20 cm,respectively.And the numbers of dormant spores were 10 cm 0 cm 20 cm.（ⅲ）With 0,10 and 20 cm contaminated soil to inoculated Chinese cabbage,the disease index of clubroot disease were 30.7,25.8 and 20.0,respectively.But with the dried contaminated soil to inoculated the Chinese cabbage,there were no disease appearance.Soil pH was closely related to the occurrence of clubroot disease in the fields.When the pH was between 5.6-5.97,the frequency of infected plants were 100 %;the pH was between 6.9-7.59,the frequency of infected plants were 45.68 %-62.96 %.When the diseased soil upturned under sun in 60,40,20 d inoculated cabbage and kale,the disease indexes were 0.47,4.4,38.2 and 0.2,1.2,24.8,respectively.The diseased root treated by flood damage and sun for 5,10,15 d inoculated cabbage,the diseased plant rate were 55.2 %,79.2 %,89.6 % and 85.7 %,100 %,100 %,respectively.The fresh root inoculated cabbage,the diseased plant rate was 84.9 %,and the disease-free soil did not cause the incidence.