Want to plant a plateau fire, royal begonia. Cardinal Haitang, what diseases and insect pests do they have and how to treat them?

Plateau begonia and other varieties should pay attention to the prevention and control of beetles, leaf rollers, aphids, marsupials, red spiders and other pests, as well as rot and brown spot. Rot disease, also known as skin rot, is one of the important diseases of many begonia, which harms trunks and branches. Generally, the disease occurs in April-May every year, with the peak in May-June, and the disease gradually relieves after July. At the beginning of the disease, waterlogging spots appeared on the trunk, and then the cortex of the affected area rotted, dried up and sank. Many small black needle-like processes, namely conidia, grow in the later stage. Prevention and control methods: remove diseased trees, burn diseased branches, and reduce the source of germs. Spray stone sulfur mixture or lime agent on the trunk in early spring. At the early stage of the disease, the diseased spot can be cut into knife marks about 0.5 cm in length and width, reaching the xylem, and then sprayed with fungicides. Jiangxi green farmers also introduced brandy begonia, purple prince begonia, golden raindrop begonia and so on. Details can be searched in official website.