River Birch Insects - Ask Extension
I have a healthy river birch in my yard and it has 4 main trunks. I noticed the bark peeling off about 4 feet up on one of the trunks with some very ...
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River Birch Insects #466186
Asked June 28, 2018, 2:56 PM EDT
I have a healthy river birch in my yard and it has 4 main trunks. I noticed the bark peeling off about 4 feet up on one of the trunks with some very small insects doing some damage. It also seems the leaves connected to this trunk have a yellow shade compared to the other 3 trunks where the leaves are a perfect green color. In some quick research on the internet, it appears I may have some type of a borer insect. I have attached some pictures and please let me know if you have any recommendations to save this beautiful tree.
Hennepin County Minnesota
Expert Response
A closeup picture of the insect involved might be helpful. However, the insects may have invaded the trunk after some other disease or injury. My first impression is that the tree has a canker but without a closer look this could be wrong. The fact that you are seeing leaf changes suggests that there is already considerable damage. I suggest that you have a certified arborist look at the tree. They will be able to give you an opinion on what is causing the problem, if the tree can be saved and what treatment might work.
Mary,
Thank you for the quick reply and I am very concerned. The insects are light in color, very small and very fast. I tried to get a good picture of one as you can see, or grab one, but they hide under the damaged bark and move quickly. The tree is about 10 years old and has always been healthy. I don't recall any damage happening to the tree or other disease as it has been maintenance free up to this point except for the routine tree trimming as new growth happens every year.
Thank you for the quick reply and I am very concerned. The insects are light in color, very small and very fast. I tried to get a good picture of one as you can see, or grab one, but they hide under the damaged bark and move quickly. The tree is about 10 years old and has always been healthy. I don't recall any damage happening to the tree or other disease as it has been maintenance free up to this point except for the routine tree trimming as new growth happens every year.
Although the picture is not very clear, they do look like aphids. See the website below. If that is the problem they are easily treated. Use a hard spray of water on the tree and they will fall off. (They cannot climb back up). Aphids secrete a sticky substance (honeydew) that attracts black sooty mold fungi. If the aphids are gone the fungi will dry up and disappear. On the other hand if you have an actual depression in the tree you will need the advice of an onsite consultation with an arborist. See: https://byf.unl.edu/4f118333-df3d-4eef-bb6d-ab963bdec4ce.pdf. Also see:https://counties.uwex.edu/outagamie/files/2016/07/Birch-Tree-Care.pdf
