What to do if black spots appear on rose leaves

1. Reasons

1. If it grows black spots, it must be attacked by black spot bacteria. The disease mainly affects leaves, branches and flower stalks. The spots usually appear on the front of the leaves, initially on the edges.

2. The spots are purple-black at first, then the diameter will reach 1.3-1-5 mm and the color will become darker. The lesions will be surrounded by yellow halos, and eventually these lesions will connect together, causing the branches to fall off.

3. This pathogen mostly harms plants of the Rosaceae family and is spread by spores. If there is water on the leaves, it can penetrate into the leaves within six hours and then decompose repeatedly. The disease may occur throughout the growing season. Especially when it is hot and rainy, the rainy season and November are the peak periods.

2. Causes of illness

The most important factor causing the leaves to get this disease is humidity. This disease can occur throughout the year, especially during hot and rainy seasons. It will form small black spots on the leaves, and most of the leaves will fall off later. There are conidia in the fallen leaves. If they are not cleaned up immediately, it will continue to be infected.

3. Treatment

1. If the disease is discovered in the early stage, the diseased branches and leaves must be removed immediately and not thrown directly into the soil. They must be burned in a centralized manner to cut off the source of the disease.

2. If the situation is very serious, you should use drugs such as metoprolol for prevention and treatment, or use thiophanate-methyl for treatment.

3. In normal maintenance, pay attention to the moisture of the soil, ventilate it, and do not sprinkle water directly on the leaves. This can prevent it well.