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Azalea Fungus Galls | by BlueRidgeKitties
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Azalea Fungus Galls

These yellow-green to cream-white to pink and eventually powdery blobs on azalea and rhododendron flowers in the area are caused by a fungus that infects plants in the Ericaceae family. When the fungus grows on azaleas it is sometimes referred to as Exobasidium azaleae, and when it grows on rhododendrons as Exobasidium rhododendri, but they all appear to be the same fungus otherwise known as Exobasidium vaccinii. I'm not sure what, if any, difference there is between these except for the host plant they're growing on. Dr. Wolfe's lab at Georgia Southern University does some research on this fungus and its influence on flame azaleas and they refer to it as Exobasidium vaccinii.


The fungus induces fleshy gall-like growths, often on buds and petals on azaleas and rhododendrons leading to disfigured flowers, that eventually become covered with a powdery spore-bearing layer. You can see these a lot on wild plants. The galls can become quite big growing to the size of a ping-pong ball to small apple (sometimes referred to as "pinkster apples") and appear to be composed entirely of juicy plant tissue when cut open. If this disease occurs on plants in your garden, the easiest way to control its spread is to simply remove the galls before the fungus has a chance to form spores.


Apparently the settlers in colonial times collected and pickled them for eating and they are reported to taste sweet. I suspect the fungus makes the plant produce sugars to feed it. I wouldn't recommend eating them though as rhododendrons (and azaleas, which are in the same genus) are actually toxic, so much so that even honey made by bees collecting nectar and pollen from rhododendron flowers can be toxic to humans.

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Taken on June 4, 2011