Camellia gall is a disease caused by the fungus Exobasidium camelliae. It is favoured by wet weather conditions.

This disease is specific to camellias. A similar disease of azaleas and rhododendrons is caused by the closely-related fungus Exobasidium japonicum.

Galls will appear on camellias from early summer.

You may see the following:

• Creamy-coloured swellings (galls) develop during summer in the place of leaves. Usually just a few galls are found, with the rest of the foliage appearing normal. Shrivelled pieces of leaf sometimes remain at the tips of the galls
• The galls can be up to 15cm (6in) in length, and variable in shape. They are often rounded or shaped like a rugby ball, but some can be forked or hand-like. They have a firm texture at first, becoming softer with age. Their surface may be smooth or wrinkled. Initially green in colour, the mature gall takes on a creamy colouration as large numbers of spores are produced over its surface

Non-chemical control

Galls should be removed and destroyed as soon as they are seen. Repeat infection is less likely if this can be done before the bloom of spores develops on the gall. If spores are already present it would be worth enclosing the gall in a plastic bag before removing it.

Chemical control

No fungicides are available to gardeners for the control of this disease.

The life-cycle of the camellia gall fungus is not well understood. The spores produced over the surface of the gall are thought to initiate new infections. Wet or humid conditions appear to favour infection.