十字花科蔬菜根肿病

 十字花科蔬菜根肿病为真菌之根肿病菌（Plasmodiophora brassicae）所引起,其休眠孢子可长期残存土中,多种十字花科蔬菜皆能被害,本病菌有生理小种之存在。土壤pH为5.4～6.5,温度18～25℃条件下危害最重。将土壤pH值调整到≥7.0,加上可交换性钙离子浓度≥1 200 mg/kg时,则不发病。实践中,石灰,石灰氮,碳酸钠皆可用来向病田土壤中添加,以使土壤pH值调整到≥7.0,并成为本病防治的主要方法。育苗用土亦需注意其pH值。避免下雨时定植及植后数天内降雨;施肥应以碱性肥料为宜。含病菌的灌溉水可用0.06％氧化钙或0.1％碳酸钠（V/V）消毒灭菌。至于根内生菌（Heteroconium chaetospira）的田间应用值得研究推广。

Clubroot of Crucifers

The clubroot disease of cruciferous plants is induced by Plasmodiophora brassicae Woronin, plasmodium fungus. Its resting spores reside for long years in the soil and could invade various cruciferous plants. This fungus composes of some bioraces. Soil pH value ranges between 5.4 to 6.5 and temperature ranges between 18～25 ℃ are the most favorable for clubroot development and thus the greatest damage could be done. Adjustment of soil pH level to 7 or up plus exchangeable calcium ion up to 1 200 mg／kg or more could suppress the disease occurrence near completely. Thus amendments of lime, calcium cyanamide or sodium carbonate to adjust soil pH value to 7 is practiced to control the disease. Cares must be taken for pH level up to 7 for seedlings raising soil, avoiding transplanting in rainy hours or expecting rain few days after tansplantings. Fertilizers should use alkaline ones. Inigation water suspecting a presence of the fungal spores could be sterilized by adding 0.06% calcium oxide or 0.1% sodium carbonate (W/V). Using biocontrol endophytic fungus, Heteroconium chaetospira in the field rewarding for further investigation.