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Willow Black Canker


Willow Black Canker

Usually appear in

Spring to Summer

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Caused By:-     The Fungus Glomerella(Phyalospora) miyabeana


Willow Black Canker symptoms appear, after Willow Scab, in late spring to summer when red brown spots appear on the leaves which die and remain on the tree. Attack kills the young leaves and causes die-back and eventually cankers of the young shoots and older branches. It is caused by the fungus Glomerella miyabeana(Phyalospora miyabeana). The fungus overwinters on dead twigs and infect new shoots the following season. Like most fungi wet weather in spring encourages the growth of the fungi. This fungus is often found with another, which causes Willow Scab Venturia saliciperda(Fusicladium saliciperdum) and both fungi together is the cause of Willow Blight. Both diseases can cause major dieback, defoliation, and death of the tree in severe cases. Picture by Mary Ann Hansen, Virginia Polytechnic Institute and State University,
See these other Cankers Apple and Pear, Bacterial, Bleeding, Canker, Cytospora, European, Horse Chestnut Bleeding, Mulberry, Parsnip, Pear and Apple, Phomopsis, Poplar Bacterial, Rose Stem and Dieback.


Black Canker is spread by rain and wind activity, which disperses the spores from the leaves and stems. Therefore it is essential to rake up fallen leaves and Prune out dead shoots to good wood. It is a good practice to sterilise the pruners between cuts to prevent spreading the disease from one branch to another as the fungi can reside in the stems. Burn all infected leaves and shoots. Spraying in the spring before bud breaking and after the leaves begin to open with fungicide may cure the disease. Avoiding stresses to the tree by feeding and providing enough water in dry times will also help. Mulching around the base to the diameter of the outer leaves will help conserve water in dry times, but avoid mulching right up tot he trunk of the tree as this will make ideal conditions for other fungi to attack the trunk.

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