1. Leaf spot

(1) Specific reasons: there is a disease called "leaf spot disease". When the disease occurs, black spots may appear on the leaves of the plant. At the beginning, there will be some small spots on the back of the leaves, which are light in color. Further development will turn into large spots with dark color and yellow rings. This disease is mainly caused by high temperature and humidity in the environment and poor ventilation

(2) Solution: first, the leaves with black spots must be removed and treated in a centralized manner, preferably burned. This can effectively prevent the spread of the disease. Next, we can spray chemicals for control. Bordeaux liquid or carbendazim can be used. The frequency is controlled to spray once every other week, a total of four or five times. In addition, we should pay more attention to ventilation and improve environmental conditions

2. Anthrax

(1) Specific reason: this disease can also cause some small black spots on the leaves. With the aggravation of the disease, the area of spots will increase

(2) Solution: first of all, we have to get rid of the diseased leaves. Secondly, spray Bordeaux liquid. In addition, the management of fertilizer and water is very important. Especially drainage and humidity

3. Illumination problem

(1) Specific reason: the plant itself is afraid of strong light. If it is exposed to strong light for a long time, it may also grow spots. If the symptoms are mild, the color will be lighter. If they are serious, black spots will appear

(2) Solution: if this is the case, then appropriate shading is needed. At ordinary times, scattered light is enough to avoid direct light