Rhododendron diseases and prevention methods

1. Physiological diseases

Diseases caused by poor environment and insufficient nutrients are called physiological diseases. For this disease, the whole plant will show obvious symptoms, and the symptoms are almost similar.

This disease is chlorosis, that is, azalea needs a slightly acidic growing environment. If it is maintained in the north, the soil and water may become alkaline, causing yellowing of the leaves. There is also small leaf disease, which is a lack of zinc, manganese and trace elements. Its leaves will become smaller and thicker, further affecting growth and flowering.

Prevention and control methods: Whatever the cause is, adjust the factor to satisfy the growth of azalea. For example, if the environment is alkaline, use weakly acidic soil instead; if it is lacking zinc or manganese, supplement it with zinc and manganese.

2. Infectious diseases

Diseases caused by pathogenic microorganisms are called infectious diseases, such as leaf spot, anthracnose, and gray mold. They have an important characteristic: their symptoms start from a central point and spread to the surrounding areas, and the symptoms at the central point are more serious. If nothing is done, the scope of expansion will gradually spread outward.

Prevention and control methods: This disease also needs to be controlled with medicines, and appropriate medicines should be taken according to the cause of the disease.

3. Coal pollution disease

Sooty mold disease is not caused by a single fungus, but by the presence of piercing-sucking pests such as aphids and scabies on the leaves. They leave some excrement on the leaves during the piercing-sucking process, and these excrement are infected with sooty mold disease bacteria and cause the disease.

Prevention and control methods: First treat the insects to eliminate the pests, and then use pesticides to kill the sooty mold disease bacteria.