1. Black spot: it is mainly harmful to the leaves. At the beginning of the disease, yellow spots of chlorosis appear on the leaves. After the disease is serious, the spots are connected into pieces, causing the whole leaves to wither and yellow. It is necessary to strengthen cultivation management and remove the diseased leaves in time. If the disease is serious, it can be cultivated in new soil. At the beginning of the disease, it can be treated by spraying chlorothalonil, which also has a good effect.
2. Brown spot: it is mainly harmful to the leaves. Some round spots appear on the diseased leaves, showing light brown to yellow brown spots. The color of the edge part is darker. In the later stage, there will be small black mildew spots on the diseased spots, which is more serious in rainy autumn. Take preventive measures in advance to reduce the occurrence of disease sources. When the disease is serious, spray a little carbendazim.
The main pest is the cotton water borer. The larva mainly sucks the leaves of the plant. When it is serious, it often eats the flesh of the leaves completely, leaving only the reticular veins. The prevention and control should pay attention to the time and timing. During the period of adult emergence, the water surface should be equipped with black light lamps to trap adults. If you use a pond, you can raise some fish in the pond, which can catch larvae.
