Camellia leaf problem

Asked June 7, 2020, 9:53 AM EDT

We have two mature camellia bushes that are showing unusual deposits on the leaves (see photo below). The plants are approximately 5 feet high and 4 feet wide and very well-established producing many blossoms in the fall and early winter.

Howard County Maryland

1 Response

Hi - The unusual leaf growths are called exobasdium leaf galls. The extended cool, wet weather this spring has been favorable for the development of these galls which are caused by the fungus Exobasidium camelliae. A related fungus, Exobasidium vaccinia, causes similar galls on azalea. Symptoms begin as puffy, light green or pinkish swollen shoot, bud, or leaf tissue. Infection occurs on emerging tissue, so most infections occur in the spring when new growth is developing. The galls eventually develop a white spore-bearing surface, so removing galls before they turn white is a way to reduce infection. Older gall tissue eventually turns brown and hardens. The disease does not affect the overall health of infected camellias or azaleas, and usually does not warrant chemical management. https://www.americancamellias.com/care-culture-resources/insects-and-diseases/exobasidum-leafgall

The black substance on your camellia leaves is called sooty mold. This is a fungus that grows on the sticky honeydew substance that is produced by soft scale insects when they feed on the sap. Please refer to our website for information on cottony camellia scale and how to manage it. https://extension.umd.edu/hgic/topics/cottony-camellia-scale-shrubs

Christa