1、 Cause of disease

Its main cause is that the plant is infected by bacteria. The infected fungus has extremely strong vitality and can successfully survive the cold winter in the plant. When the weather is warm at the beginning of the next spring, it will begin to recover its vitality and infringe on the growth of the plant. At the beginning, from the middle, it gradually turns from grayish brown to grayish white, and gradually sinks down. There is also a yellowish brown line on its edge. Yellow powder like rust grows on the back of the leaves, and this is the source of bacteria

2、 What should I do

1. This is often caused by too much water, which makes the roots of plants very fragile and poor growth. Therefore, it is necessary to cut off the location of the lesion first, and then burn the cut leaves. If it is densely planted, it needs to be dredged to avoid over dense planting

2. In the spring season, it needs to be properly sprayed with some Bordeaux solution for protection. If there is a disease, it can also be sprayed with Triadimefon solution and water. Or use the mixture of chlorothalonil and tobuzin with bactericidal effect to spray the whole plant can also be very effective