油菜根腐病、从油菜苗期开始,直到收获前整个生育期均可发病,尤以苗期为害最重,是油菜重要病害之一。一、发生规律。油菜根腐病是一种真菌性病害。病菌经菌丝和菌核在土中或病残株中越冬越夏,病菌在土壤中能存活2～3年,带病土壤是主要传染来源。混有油菜病残体(如秸秆、角果荚壳等)所积造的土杂肥也可成为初侵染病源。病菌发育最适温度为25℃左右。病菌主要借雨水传播,其次借雨水溅射或农事 Rape root rot, from rapeseed seedling stage, until the harvest before the disease can be the disease, especially in the seedling stage the most important, is one of the important diseases rape. First, the law occurs. Rape root rot is a fungal disease. Bacteria by mycelium and sclerotia in the soil or diseased plants overwinter summer, the bacteria in the soil can survive for 2 to 3 years, sick soil is the main source of infection. Mixed with rape disease residues (such as straw, pod shell, etc.) of the earth can also become a source of infection. Pathogen optimum temperature of about 25 ℃. Germs spread mainly by rain, followed by rain or agricultural splashes