Rose black spot is a prevalent fungal infection that affects the health and longevity of roses, characterized by purple and black spots on leaves, yellowing foliage, and premature leaf drop. Gardening expert Ish suggests using a simple solution of one teaspoon of baking soda mixed with 500ml of water as a natural antifungal spray to combat this issue. The solution should be applied lightly once a week. Additionally, adding a splash of washing up liquid can improve adhesion to the leaves. Preventive measures include ensuring adequate airflow by trimming dense foliage, proper watering, and planting salvias, which are known to have antifungal properties. The Royal Horticultural Society advises maintaining good garden hygiene by removing fallen leaves and avoiding the use of fungicides, which can harm biodiversity and soil health. By following these guidelines, gardeners can effectively manage and prevent the spread of black spot in their rose plants.