A diseased lime was investigated with the object of determining the cause of disease. The only fructifications present were those of Ustulina vulgaris Tul.
2
The causal organism was isolated and proved to be Ustulina; this was confirmed by reinfection and subsequent isolation.
3
The tree was cut into sections and the extent of the disease in the stem and root was established.
4
Microscopic examination showed that the fungus attacked the cell walls of the tracheids, leaving the vessels, rays and parenchyma practically unaffected.
5
The distribution of the fungus mycelium in the timber was determined by microscopic examination and the types of fungal penetration described.
6
It was concluded that Ustulina causes a white rot of lime.