Symptoms: the perennial old plants are easy to be infected with this disease. After being infected with rust, the front of the leaves will start to turn green, and the round brown powder can be seen on the back. When the disease is serious in the later stage, the whole leaf will gradually turn yellow and wither until it falls down, and the growth of the whole plant will become very weak.
Prevention and control: take preventive measures, disinfect the seeds before sowing, and spray Bordeaux solution on the plants in spring and summer. In the early stage of the disease, powder rust Ning, methyltobuzin, chlorothalonil can be sprayed once every 7-10 days, two or three times in a row.
Symptoms: at the beginning of the disease, there will be small brown spots on the surface of the leaves. As the disease worsens, the spots will gradually expand into a round or oval shape, the central part is gray white, and the edge is reddish brown.
Prevention and control: spray chlorothalonil at the beginning, once every 10 days, 3-4 times continuously.
Symptoms: this kind of insect pest is easy to reproduce when it is dry and hot, and it will stab into the leaves and suck the juice inside, making the leaves appear grayish yellow or plaque. In the later stage, it may cause the leaves to wither and fall off, and in serious cases, the leaves of the whole plant will fall off.
Control: when the pest is serious, spray the plant with medicine, such as abamectin emulsion, which can have good effect.
