Black spot is the most common disease of roses. And if this is not given attention, then it spread with time and becomes uncontrolled. This leads to considerable loss of rose plants. Black spots are basically black spots on the surface of rose leaves, which move along with time, With it, the yellow spots are all around the leaf, and at the end, the leaves fall. Fungus Diplocarpon rose is the reason for this. If it is not treated at a time, all the leaves will fall off one by one and your plant will become naked. The plant will become weak and the production of flowers will end.
How to prevent Black Spot:
Although you may not be completely prevented from black spot disease, the risk of black spot fungal infection can be reduced if you take care of the plant in the following manner. There are some general tips to prevent the black spot:
If the leaves are in contact with water for seven consecutive hours, then black spot spores get a chance to grow. To avoid this you add water early in the morning. This will give the leaves a chance to dry and the spores will not grow. Yes, but if it rains at night or if you add water every night, then you will not be able to stop this disease. Just watering into the soil of the plant, if you watering in the leaves, the fungus will spread from one leaf to another, and eventually spread to the entire plant.
2.Space between plants:
You should make distances between your rose plant. In the nearby plant, the air circulation does not get well and the leaves remain wet. By which the fungus gets a suitable environment to develop. Do not keep the rose plant in a place where there is too much shade. By the way, you can use the shed to save the leaves from getting wet from the rain.
3.The resistant Rose Plant:
Nowadays many species have been developed which are resistant to black spot disease. Keep in mind that there is a difference between immune and resistant. Black spot disease can also be found in the resistant rose, but it is more likely to bear the disease than other roses. Some resistant rose varieties are Henry Hudson, Jens Munk, David Thompson, Charles Albanel, John Cabot, and Reine des Violettes, Plena rugosa. for more details read.
Rose plants prefer full sun, so choose a location for the rose plant where there is at least 8 hours Sunlight.
5. Feeding :
Regular feeding is important for rose plants, its provides the nutrients your plants and make healthy . its help to protect from disease.
6.Burn infected leaves:
Clean the infected fell down eaves immediately. Do not use these leaves in the form of compost or in the form of a mulch. It would be better if you burn these leaves.
Gate rid from Black Spot to spray your plants:
If the black spot is a problem in your plant then you will have to spray in the early spring. Here are some simple tips you can use.
1. Baking soda spray:
Baking soda is a very good fungicide, you have seen black spots on rose leaves or fungal diseases in the plant, it is very useful. It is also effective in grapes and other vines. 4 spoon baking soda dissolve in a gallon of water and use it. Baking soda spray works better and this also protects the plant from powdery mildew.
2. Neem oil:
Neem oil is an organic fungicide and insecticide. It works from inside the plant’s system. Therefore, it is not neutralized after washing with rain after spraying, although it can burn the leaves of the plant in the warm sunshine. And if you have used sulfur then you should not use Neem oil within 2 weeks.
3. Use of Sulfur:
Sulfur is used to control pests and to get rid of fungal diseases. However, it can also be light toxic for humans and animals so, you should protect when spraying it. Never spray it with metal utensils, it can damage it. Use a plastic sprayer and leave the plant in the sun.
5. Insecticidal soap spray:
If the use of insecticidal soaps spray is done regularly on leaves, fungal diseases can get rid of them. It is a fungicide made of copper sulfate and hydrated lime, if it is sprayed mixture with water, you can get rid of some insects, but this can burn the plant leaves, so it’s spray should be done in the spring, Before come out the plant new leaves.
Sources: The Spruce