Birch Tree Rot or Fungus - Ask Extension
Wondering if this is a type of fungus, rotting, or canker? Found around birch trees in a park within the last 2 weeks.
Knowledgebase
Birch Tree Rot or Fungus #847744
Asked August 29, 2023, 10:17 AM EDT
Wondering if this is a type of fungus, rotting, or canker? Found around birch trees in a park within the last 2 weeks.
Ottawa County Michigan
Expert Response
Hi Kelli,
The white appearance of the branches is caused by aphids; there are hundreds of tiny insects on the branch. Each one is feeding on the sap from the birch tree.
As the insect feeds, it also excretes a sugary substance, called honeydew, on the surfaces below. The honeydew provides an ideal substrate for the growth of black sooty mold fungus, which will not harm the tree.
While some branches may be weakened by the aphids, it is no cause for alarm. Aphids are a natural part of the forest ecosystem, and a tree losing a branch, or even dying are also part of the natural system. So, no action is recommended.
If you have any questions, please feel free to reach out.
Thank you,
-Julie
The white appearance of the branches is caused by aphids; there are hundreds of tiny insects on the branch. Each one is feeding on the sap from the birch tree.
As the insect feeds, it also excretes a sugary substance, called honeydew, on the surfaces below. The honeydew provides an ideal substrate for the growth of black sooty mold fungus, which will not harm the tree.
While some branches may be weakened by the aphids, it is no cause for alarm. Aphids are a natural part of the forest ecosystem, and a tree losing a branch, or even dying are also part of the natural system. So, no action is recommended.
If you have any questions, please feel free to reach out.
Thank you,
-Julie
