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Azalea gall attacks certain rhododendrons and azaleas out of doors and is often seen on indoor pot-grown plants of Rhododendron simsii, the popular Indian azalea, obtained from florists.
This is a common disease caused by the fungus Exobasidium japonicum that disfigures, but does not kill, rhododendrons including azaleas. It spreads by airborne spores.
Azalea gall is a very distinctive and curious-looking disease;
There are no fungicides available to amateur gardeners for the control of azalea gall.
The spores of the azalea gall fungus are insect or air-borne, and spread the disease from infected to healthy plants. On germination of the spores the fungus enters the tissues of the host, but can then have a long incubation period so that symptoms may not appear until several months after infection. However, very little detail is known about the life-cycle of the fungus.
A closely-related fungus causes a similar disease on camellias.
Disposing of diseased material
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