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| witches besom (Taphrina spec.) |
| Witches besom are highly branched out sprout
systems that emerge from proventitious or adventitious buds.
They are caused by a sac fungi. In extreme cases, this can hinder
the tree growth. |
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| (Marssonina betulae) |
| Small black spots that grow together to form
larger spots. Solitary outbreaks are not dangerous for the tree. |
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| Leaf necrosis (Asteroma microspermum) |
| Large light-brown spots on the leaves. Solitary
outbreaks are not dangerous for the tree. |
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| Canker (Nectria galligena) |
| Fungi that leads to the breaking off of bark.
Affected twigs and branches should be removed and burned. If
the trunk is affected, then an expert should be called to remove
canker. |
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| birch true bug |
| They occur often in large amounts
in birch trees. They are pesky, but not dangerous for the tree.
A chemical treatment is controversial . |
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| Wood excrescence
? Cause is unknown. |
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| Gall midge (Aceria rudis rudis) |
| Leaf deformation caused by a gall midge.
Not dangerous for the tree. |
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Daedalea unicolor
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Poria obliqua
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