DISEASE

NAME
Sunscald
Environmental (Sun)


Description
Excessive or sudden direct light on the plant combined with high temperatures.

Symptoms
Central parts of the leaf become burnt turning the areas yellow. This area soon becomes brown to black causing the death of the leaf. In climates where it snows unripe wood is damaged by hot spring temperatures in conjunction with Winter Damage. In this case the leaves and stems turn reddish from the excessive cold and when temperatures increase transpiration is inhibited by the frozen soil and poor leaf development, resulting in die back.

Ctenanthe oppenheimiana Aucuba japonica

Favoured Conditions
Hot mid day, full sun exposure to plants that normally are protected, or excessive heat waves that cause damage to plants which otherwise tolerate full sun. Plants are most susceptible during spring as the new growth develops.
     
Affected Plants
All plants can be damaged from Sunscald.

Camelliaspecies

Camellia reticulata and Camellia japonicaare sensitive to excessive light turning the leaves brown and Camellia sasanquais less venerable.

Banksia robur       Bergenia x schmidtii

Hoyaand Buxusspecies, Aucuba japonica, Banksia robur and Bergenia x schmidtii are also sensitive to excessive sun.

Cyathea australis (Tree Fern)

Fernsare particularly susceptible to variations in light intensity, combined with high temperatures.

Non-chemical Control
Select plants that tolerate full sun, or protect existing plants from excessive light.

Chemical Control
Not applicable in this case.