What if the rose leaves have black spots?

First, reasons

1. If it has black spots, it must have been eroded by black spot pathogen. The disease mainly affects the stems of leaves, branches and flowers. Spots often grow on the front of the leaf and start at the edge of the leaf.

2. At first, the spot is purplish black, then the diameter will reach 1.3-1-5 ", and the color will be darker. There will be yellow halos around the plaques, and eventually these spots will be connected, causing the branches to fall off.

3. This pathogen mostly harms Rosaceae plants and spreads by spores. If there is water on the leaves, it can invade into the leaves within six hours and then decompose repeatedly. It is possible to get the disease throughout the growing season. Especially when it is hot and rainy, the rainy season and November are the peak periods.

Second, the cause of illness

The most important factor for leaves to get this disease is humidity, which can occur throughout the year, especially when it is hot and rainy. It will form small black dots on the leaves, and most of the leaves will fall off in the later stage. There are conidia in the fallen leaves, which will be infected all the time if they are not cleaned up immediately.

III. Methods of treatment

1. If the disease is found at the initial stage of the disease, the diseased branches and leaves should be removed immediately and should not be thrown directly into the soil. It should be burned centrally and the source of the disease should be cut off.

2. If the situation is very serious, it should be prevented and treated with drugs such as meparin, or topiramine.

3, in the normal maintenance, we should pay attention to the soil moisture, give it ventilation, do not directly sprinkle water on the leaves, so that it can be well prevented.