Hello,

The image of the branches with leaves appears to have aphids. It is hard to tell. It’s quite possible that the black fungus on the trunk of your paper birch (Betula papyrifera) is sooty mold, which commonly occurs due to aphid infestations. Aphids produce a sticky substance known as honeydew, which can be a substrate for sooty mold development. More information at these links:

betpapa.pdf (ufl.edu)

ENH255/ST096: Betula papyrifera: Paper Birch (ufl.edu)

Birch: Aphids | Hortsense | Washington State University (wsu.edu)

Sooty mold is a black coating on leaves, stems, and tree trunk.

In the case of heavy aphid infestations, the growth of sooty mold can be significant, leading to a black appearance. It’s important to manage the aphid population to prevent further damage and the spread of sooty mold. You might want to consider consulting with a local arborist or MSU Plant and Pest lab for advice on effective and environmentally responsible treatment options.

OPTION 1:

To confirm and precisely identify the problem, I recommend that you email all your images to the MSU Plant & Pest Diagnostics Lab.

IN ADDITION TO YOUR IMAGES, PLEASE SEND AN ADDITIONAL CLEAR AND CLOSE-UP IMAGE OF A:

Branch with leaves – with aphids

The experts there can also provide you with the best treatment options. Their email is <personal data hidden> - Please include your name – The lab will let you know if they need a sample sent.

FYI – The lab may also ask for additional images.

Their website is at this link:

Plant & Pest Diagnostics (msu.edu)

Their Contact Information is at this link:

Contact Us - Plant & Pest Diagnostics (msu.edu)

This link will explain the details of submitting a sample to MSU Plant & Pest Diagnostics Lab:

Submit Samples - Plant & Pest Diagnostics (msu.edu)

OPTION 2:

You can consult a local certified arborist for a more detailed onsite assessment and personalized advice. To find a certified arborist in your Zip Code, go to this link:

Find an Arborist (treesaregood.org)