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Ash decline

Appearance: This term refers to the loss of vigour and health of a tree; not to any specific disease or disorder. Slower growth of branches on the tree is the first sign of ash decline; this leads to short spaces between leaves and bunching of leaves at the end of branches. Leaves are smaller, and turn pale green or yellow. The leaves in the upper part of the tree look sparse. Trees will often show fall colour and drop their leaves early.

Other common symptoms include yellow to reddish spots and rings on leaves as well as light green to cream line patterns or other coloured spots or streaks. Cankers or dark sunken spots can sometimes appear.

Cause: Decline is caused by multiple or unknown factors.

Growing Season: Not applicable.

IPM Toolkit:

Preventive tools:

  • Ensure you do everything to keep your tree healthy, which includes mulching, watering, fertilizing and pruning.

Physical tools: Not applicable

Biological tools: Not applicable

Least toxic chemical tools: Not applicable