Rose black spot

Rose black spot is a fungal disease that infects roses. Purple or black spots develop on infected leaves. The leaves often turn yellow and fall off early.

Damaged leaves and the loss of leaves reduce photosynthesis, the process by which the plant makes glucose using light. With less glucose available for growth, the rose grows less.

The fungus can spread through the environment in water or wind. Rose black spot can be treated with fungicides and by removing and destroying affected leaves.