What happens to rose leaves infected with Rose Black Spot?

Rose Black Spot is a fungal disease caused by the pathogen Diplocarpon rosae, which affects rose plants. When leaves are infected, they typically exhibit specific symptoms that relate to their health and vitality. The leaves usually turn yellow, a process known as chlorosis, which occurs because the presence of the fungus disrupts the plant's ability to photosynthesize effectively. This is due to damage to the leaf tissues and loss of chlorophyll, which is vital for the green color in plants.

Furthermore, as the disease progresses, the affected leaves may also fall off the plant, which indicates that the plant is struggling to maintain health. This leaf drop is a survival mechanism; it prevents the plant from wasting resources on damaged leaves and redirects energy towards recovery and new growth. The overall impact on the rose bush can lead to stunted growth and reduced flowering, making it crucial for gardeners to manage this disease effectively.

In contrast, the other options do not accurately describe the impacts of Rose Black Spot on the leaves.