Symptoms: the disease mainly occurs on the leaves. At the beginning, the disease spots are brown round spots with gray white inside and reddish brown on the edge. At the end, the disease spots will dry up with black particles. The disease is serious in rainy season, and the occurrence of bacteria is likely to be greater.
Prevention and control: clear the sick and disabled in time, spray regularly carbendazim and other drugs, which can play a good effect. When the trees are still small, if any leaf spot is found, it is necessary to remove the diseased leaves in time, and then concentrate to destroy them.
Symptoms: the reproduction speed of this pest is very fast, and it is relatively concentrated, and the population is relatively large, which has a great impact on Magnolia grandiflora. The period from May and late June to August is a period of serious harm.
Prevention and control: pay attention to avoid mechanical damage during planting, strengthen maintenance at ordinary times, and timely fill the incomplete holes for trees.
Symptoms: it will appear twice a year, mainly in the leaves, branches and young shoots. In July and September, it is the peak period, and the harm is relatively large.
Prevention and control: in the first ten days of April and the last ten days of August, these two prevention and control periods can also be spray prevention and control, such as Huabao, zhichonglin, etc.
