一、危害症状:大蒜叶病又名黑斑病,主要危害叶片和梗。病菌在土壤中的病残株中越冬,并随雨水气流传播。侵染后先从叶尖开始发生,然后逐渐向下扩展,初期呈白色小点,后为紫褐色的椭圆形或纺锤形病斑,潮湿时病斑上密生有黑色粉状霉层。发病严重时叶片和花梗从发病部位折断,引起病叶枯死,严重影响产量和品 First, the harm symptoms: Garlic leaf disease, also known as black spot disease, the main hazards leaves and stems. Bacteria winters in diseased plants in the soil and spreads with storm water currents. Infections started from the tip, and then gradually extended downward, initially a small white point, followed by a purple brown oval or spindle-shaped lesions, damp spot on the dense black mold mildew. Severe disease leaves and pedicels from the incidence of broken parts, causing diseased leaves dead, seriously affecting the yield and product