根腐病、赤斑病、青枯死杆病和锈病是蚕豆四大主要病害。 根腐病是一种真菌性病害。发病后,植株矮小、叶片发黄、主根和茎根变黑、根瘤菌减少。但最明显的特征是植株下部叶片的叶缘变黑,严重时整叶变黑焦枯。此病一旦大发生,可使蚕豆减产3～5成。在防治上,如果病害已经发生,可及 Root rot, red spot, green dead stems and rust is the four major diseases Vicia faba. Root rot is a fungal disease. After the onset, the plants were short, yellow leaves, black roots and stems, rhizobia decreased. However, the most obvious feature is that the leaf margin of the leaves of the lower part of the plant becomes black, and in the severe case the whole leaf becomes dark and scorched. Once the disease occurs, can make broad bean cut 3 to 5 percent. In the prevention and control, if the disease has occurred, we can