Brown spot disease is a common disease of Polygonum viviparum. Generally, if brown spot disease occurs, it will appear on the leaves. The disease spots appear on both sides of the leaves. Most of them are round or similar to round patches. When it is serious, black molds, namely fungal spores, will appear.
The brown spot of Polygonum hydropiper is caused by a kind of fungus, which gathers on both sides of the leaves of Polygonum hydropiper.
The brown spot of Polygonum viviparum is caused by the epiphyte, Cercospora Polygonum. The first thing needed for this kind of disease is the conditions suitable for the growth and reproduction of epiphytes. Generally, Cercospora Polygonum will overwinter in the form of mycelium in the diseased remains of Polygonum viviparum. In the spring of next year, as long as the environmental conditions are suitable for the growth of Cercospora Polygonum, then Cercospora Polygonum will start to grow and reproduce, and a large number of them will grow. Spores, and then with the help of natural wind or rain, watering when the transmission, sometimes there may be secondary transmission phenomenon, is the plant to increase the chance of infection.
Note that in North China and Northeast China, the occurrence of brown spot may be in August.
Before the onset of melasma, you can remove the remains in the plant at the end of autumn and the beginning of winter, reduce the source of the disease, and reduce the incidence of melasma
In the early stage of black spot, we can take the way of drug treatment, spray some 1500 times of 50% Benazolin wettable powder, which can play a certain role in prevention and treatment.
