Symptoms: it is mainly harmful to leaves, but also spreads to tender stems, flowers, fruits and other parts. At first, irregular white powder will appear on leaves. Later, with the severity of the disease, the leaves are covered with white powder layer. In autumn, small yellow dots will appear on the white powder layer. Later, it will gradually turn dark brown, and then it will turn yellow and twisted.
Prevention and treatment: if you are ill, pull out the sick plant in time, and then remove the sick leaves, it can reduce the source of infection. When the disease occurs, it can be sprayed with medicine such as methylthiophanate, Triadimefon, carbendazim, etc.
Symptoms: the disease also damages the leaves, resulting in dark brown round spots around the leaves, concentric rings on the surface of the spots, gray brown in the middle of the spots in the later stage, and black small particles.
Prevention and control: spray once every 7-10 days from the early stage of the disease. There are many chemicals to choose, such as zinc Daisen, thiram, chlorothalonil, etc.
Symptoms: mainly the larva nibbles on the leaves, resulting in incomplete leaves, which will damage the flowers in serious cases.
Prevention and control: the larval stage is mainly spraying, which can be used to kill emulsifiable oil and trichlorfon, etc. in the later stage of adult emergence, it can be used to trap and kill adults with black light lamp.
