Leaf spot disease caused by Cercospora fungi

The disease was found on Cartland in the United States. The disease is not serious and usually occurs on weak or injured leaves. At the beginning of the infection, a small yellow area appears on the back or front of the leaf, and as the disease develops, the disease area turns brown and finally becomes a black oil-stained area. The fruiting body structure of the fungus with black protuberance appeared on the older spot, which was the conidium of the pathogen. The pathogen was identified as Diplodia laeliocattleyae. As this disease is rarely found, effective control measures have not been found. Generally speaking, only all diseased leaves can be removed and destroyed to reduce the source of infection. Considering that the infection of chromophore to other plants is through wounds, and perhaps to orchids, care must be taken to avoid damaging the plants. (Liu Zhongjian)