Category: Disease

Symptoms: White powder on the leaves and stems followed by black blotches

Parts Affected: Leaves and Stems 

Cause: Powdery Mildew.

Description: This disease usually occurs in the warmer months and can be fairly persistent. Some varieties are more prone to this disease than others. Powdery Mildew attacks a wide range of plants. it is worst in areas of the garden that have low air movement. In some gardens, you can have two of the same varieties, one with the disease and one without, all due to the microclimate where each is planted.

Remedy: There are two methods of attack for this disease. 1) Spray with a rose fungicide such as Triforine to control the disease if you know your garden is susceptible to this disease. 2) Plant a resistant variety.