Prevention and Control of Rose Powdery Mildew

Disease symptoms

When this disease occurs, the leaves of the rose will turn yellow, wither, and curl. The flowers sometimes fail to open normally, and the surface of the plant will be covered with a layer of white powdery substance. In severe cases, it can affect the normal growth of the plant.

Onset time

May is the common peak period of the disease, and June to July is the infectious period.

Disease environment

1. In warmer climates, this disease is more likely to occur regardless of whether the air is humid or dry;

2. Excessive nitrogen fertilizer use makes the soil where the crops are grown seriously lacking in potassium and calcium, which makes the disease more likely to occur;

3. Poor light transmission and ventilation, coupled with the plants being too dense, will aggravate the disease;

4. This disease is prone to occur when the temperature difference of cultivated plants is too large;

5. This disease is prone to occur when the soil is too dry.

Prevention and treatment methods

Prevention: When growing plants, observe the soil more often, water them appropriately, and try to balance the nutrients when fertilizing, instead of applying too much fertilizer, so that the plants can improve their own resistance. Prune them in a timely manner, especially when you find diseased branches and leaves such as yellowing and withering, clean them up thoroughly. Pay attention to the light and ventilation environment. Roses should be placed in a location with plenty of sunlight and can be directly exposed to the sun, and there should also be good light and ventilation.

Treatment: Some bactericidal and sterilizing drugs can be used for treatment. The soil can be sterilized before planting. During the growing period, the surface of the plants can be sprayed with bactericidal liquid medicine. The best time for spraying is between 8 and 10 in the morning and between 4 and 7 in the afternoon.