| Causal agent: |
Alternaria tenuis |
| Symptoms: |
Beginning at the edge or tip the leaves become brown in the intercostal fields and die. A black, velvety coat develops on the tissue (bearer of conidia). |
| Epidemiology: |
The causal agent is a parasite which infects first those leaves being primarily damaged by other causes, e. g. due to mechanical damaging of the leaves after virus infections, drought damage or lack of nutrients. |
| Economic importance: |
As the economic importance is only secondary, no control measures of the disease are needed. |
