How to recognise it
Pestalotiopsis guipini causes large, yellow-brown spots with dark edges. These appear on the leaf edges and spread inwards. They look similar to chlorosis symptoms due to iron deficiency, which is common in camellias.
Phyllosticta camelliae spots are smaller and brown with reddish borders, often they are circular in appearance.
Why it’s a problem
The fungi themselves do not pose a threat to the plant, although affected leaves look unslightly. However, they often occur as a result of poor growing conditions, which could cause additional, more serious, diseases to take hold.
Where you are likely to find it
On camellias, but particularly serious on those growing in warmer climates or in glasshouses and where there is a nutient imbalance or if the camellias are overwatered.
How to prevent it
Ensure your camellias are growing in optimal conditions, are well fed with appropriate nutrients and are not overwatered.
How to get rid of it
Affected leaves should be removed and destroyed (do not put them on your compost heap), including any fallen leaves, so they do not pass the fungus to neighbouring leaves. Growing conditions should be improved, particularly nutrients in the growing media, and watering routines/drainage.
Is it good for anything?!
No, but it does provide an indicator of poor nutrition or overwatering, which can then be corrected before a more serious disease takes advantage of the plant’s weakened state.
Other useful information
Pestalotiopsis guepini can also be a cause of Rhododendron leaf spot.