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菌核病是油菜生产上的主要病害,它从苗期到成熟期,都可造成危害,尤以中后期发病最普遍,危害最严重。菌核萌发和产生子囊盘的温度为5～20℃,土壤相对湿度为70%～80%。每年3～4月份春暖多雨,气温和湿度都适合菌核的繁殖侵染。在这种温、湿度条件下,越冬菌核在土壤中大量萌发,产生子囊盘,散发出子囊孢子,随风传播。如果子囊孢遇上油菜开花结荚期,油菜本身抵抗力弱,菌核病菌最容易侵入油菜植株危害。病菌侵入油菜植株后,分解茎杆细胞的胶织物,使茎杆表面纤维破裂如麻,茎杆折断倒伏,造成子粒不实,千粒重减轻。后期如剖开茎杆,茎内常有白色棉絮状菌丝或黑色鼠粪状菌核。防治措施:(一)预防方法。开春以后,油菜封行之前,要坚持除草1～2次,将菌核及其发芽长出的子囊盘埋入土中,使孢子不飞散。油菜苔蕾期,要控制氮肥施用量,增施磷、钾肥,防止徒长,增强抗病力。
Sclerotinia sclerotiorum is the main disease in rapeseed production. It can cause harm from the seedling stage to the mature stage, especially in the mid and late stage, with the most serious and serious harm. The temperature of the sclerotia germinating and producing ascus was 5 ~ 20 ℃ and the soil relative humidity was 70% ~ 80%. March to April every year, warm and rainy, temperature and humidity are suitable for reproduction and infection of sclerotia. In this temperature and humidity conditions, the overwintering sclerotia in the soil a large number of germination, resulting in ascus pan, exuding ascospores, spread with the wind. If the Ascocapsalum rape flowering pod, rape itself weak resistance, Sclerotinia most likely to invade the rape plant damage. Germs invade the rape plants, the decomposition of stem cell glue fabric, so that the stem surface fiber rupture, such as hemp, stem broken off lodging, resulting in false grain, grain weight reduced. Later, such as cut open the stem, the stem often white cotton-like mycelium or black rat feces-like sclerotia. Prevention and treatment measures: (a) prevention methods. After the spring, rape seal line, we must adhere to the weeds 1 or 2 times, the sclerotium and its germinated ascus capsule buried in the soil, so spores do not fly. Rape in the rapeseed period, to control the amount of nitrogen fertilizer, phosphorus, potassium, prevent leggy and enhance disease resistance.