What Is Wrong With My Rose Bush Leaves?

Identification

• Rose bushes are susceptible to black spot fungal disease caused by Diplocarpon rosae. The disease is more prevalent in regions with wet and cool weather. Miniature rose varieties are more prone to the disease.

Symptoms

• The infection is characterized by the appearance of black spots on foliage uppersides. There is no accompanying growth on the lower sides of the leaves. As the disease progresses, the black spots with feathered borders also spread to succulent stems. There is appearance of black fruiting bodies within the spots. The spots develop yellow margins experience defoliation.

Management

• Avoid planting in areas of high humidity and do not use overhead sprinklers as wet foliage favors growth of fungus. Plant rose bushes in areas with good ventilation. Keep plant area clear of fallen foliage and debris. Use triforine or chlorothalonil as effective chemical control options.