DISEASE

NAME
Anthracnose - Rose
Sphaceloma rosarum

Description
This fungus is a casual organism that attacks leaves and stems. There is another Anthracnose (Elsinoe rosarum) that infects Rosa species and has the same characteristics.


Symptoms
Circular black spots appear primarily on the leaves but may also occur on the stems or flowers. The spots have a definite margin that may turn purple with age. As the spot enlarges the centre dries and may fall out giving the leaf a shot hole appearance. The leaves become yellow and may fall prematurely.

     

Source and Dispersal
The fungus is dispersed by wind from other infected plants or parts of plants.

Favoured Conditions
The fungus prefers cool humid climates and is not commonly seen in warm coastal regions.

Affected Plants
Commonly attacks roses.

Non-chemical Control
Avoid watering plants from above or wetting the foliage especially in the late afternoon. When planting allow space between each plant for air circulation. Remove affected foliage or wood by pruning and dispose off site.

Chemical Control
Regular spraying during the periods that are favourable for fungus development. Fungicides include;
Systemic types, Biteranol, carbendazim, triforine
Protectants; chlorothalonil, copper oxychloride, mancozeb, thiram, zineb
Note
Always read the label for registration details and direction of use prior to application of any chemicals.