Advice
RHS Help & Advice
Camellia leaf blight
Hosts
Camellia species. Can also attack Rhododendron, but apparently unimportant on this host. Other unrelated hosts have been recorded in other countries.
Symptoms
Discoloured
patches on leaves and petioles, which turn pale brown. Under
conditions of high humidity, pin-prick sized black spots (fruiting bodies) appear
in the brown dead patches. Badly affected leaves fall. Mainly
a problem in young plants during propagation, but can also
attack larger plants. Probably more common than reports suggest,
but seldom recognised.
Biology
Caused by the fungus Monochaetia karstenii. The tiny black fruiting bodies produce the spores of the fungus, which are dispersed in water. Like many of the fungi that cause leaf spots, the fungus has been little studied and few details of its biology are available.
Control
Remove affected leaves promptly and destroy. Where possible, keep leaves dry to prevent dispersal and germination of the spores. There are no fungicides available to home gardeners with specific recommendations for the control of this disease. The fungicides myclobutanil (e.g. Bio Systhane Fungus Fighter) and penconazole (Scotts Fungus Clear) are labelled for the control of some other diseases on ornamental plants, and may give some control of camellia leaf blight.