Coral spot of wisteria

Disease Information

Coral spot

Nectriacinnabarina

Coral spot is a fungal disease of woody plants causing branches to die back. Small coral-pink raised spots (pustules) form after the branch dies. Coral spot often indicates that the plant has been weakened by other factors.

Symptomsand damage

Coral spot, so-called because after affected branches die they develop pinhead-sized pink fungal pustules, is a disease caused by the fungus Nectriacinnabarina. It causes die-back of branches of woody plants, but the causal fungus is a weak pathogen and its presence often indicates that the plant also has other problems.

Among broadleaf trees and shrubs, AcerAesculus (horse chestnut), Carpinus (hornbeam), Fagus (beech),Juglans (walnut) and Tilia (lime) are among the more susceptible to attack. It is rarely found on conifers.

The small coral-pink fungal pustules may be seen at all times of year.

You may see the following symptoms:

·         Die-back of branches, usually those that have been broken or pruned further up

·         After death, pinhead-sized pink pustules of the causal fungus appear on the bark

Management

Cultural control

Always prune in dry weather. When carrying out routine pruning, cut branches through the collar (ring of slight swelling found at the base of branches). Healing of wounds occurs most quickly here, compared to leaving stubs (snags) or cutting flush with the bough or trunk. If die-back occurs after pruning, remove dead material to avoid further infection.

Prune out infections promptly and cut back to healthy wood. Do not leave dead wood to moulder and generate spores in damp corners of the garden.

Chemical control

There are no specific fungicidal controls for this disease.

If it is necessary to prune in wet weather when risks of infection are high, or if the plant has previously shown a particular susceptibility to the problem, use a wound paint (VitaxMedo, Bayer Garden Arbrex Seal and Heal, Growing Success Prune and Seal) to protect the cut.

However, wound paints are not recommended for routine use as they are thought to interfere with healing and may even provide a better environment for rots

 



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