城市河区常见病虫害的防治一、河区常见病害１杨柳腐烂病：主要为害杨柳树枝干，５—６月为发病盛期，使树皮腐烂。２桃树流胶病：５月下旬至６月下旬，８月上旬至９月上旬为发病高峰，形成枝干溃疡病。３花木白粉病：主要为害黄杨、月季、丁香的嫩叶及嫩枝，使病梢... Prevention and treatment of common pests and diseases in urban river areas 1. Common diseases in river areas 1. Yangliu rot disease: The main willow branches are damaged, and the period from May to June is the peak of the disease, causing the bark to decay. 2 peach meliorating disease: late May to late June, early August to early September peak incidence, the formation of ulcer disease. 3  flowers powdery mildew: the main damage Boxwood, rose, lilac and young shoots, so that disease tip ...