Green-White Mold?

Asked April 10, 2020, 7:09 PM EDT

What can I do to stop the green/white mildew looking stuff from killing my tree?

Nassau County New York

5 Responses

Luckily, these are not mold, but lichens! They are not in any way harming the trees. You can watch a video from Penn State about them here:

Hi Esther,

Thank you for the quick response! It's good to know the Lichens are not causing damage to my tree. As the video suggests, I would not have noticed them if I did not notice how some sections of my tree have become bare. Now onto the second mystery.

You're very welcome! If we can help with the second mystery, let us know.

Take care!

Thanks for the previous information, but do you have any strategy for stopping the tree becoming bare?
I am glad to know that lichens are harmless to the tree, so I guess its coincidence that those are the branches that are bare. As you can see in the other pictures these branches are lower to the ground, so maybe available sunlight may be an issue. In one picture, there is something oozing from the tree (pinkish). Typically, I would just trim the leafless branches, but before I committ id ike to get your opinion.

Thanks again for your input. If you need more photos or video, please let me know.

The lichens are not harming your tree but they only form on plants that are growing very slowly or not at all. For that reason, they frequently indicate an underlying problem that is unrelated to the lichen.

The oozing that you observed may be caused by and injury to the tree, insect activity of a bacterial or fungal disease. A full examination of the tree is necessary to determine what is causing the problem and there are too many parts of a tree, from roots to branch tips, for us to do that by photo or video. You should contact a certified arborist to look at your tree in person. You can find a certified arborist working in Nassau County through the International Society of Arboriculture (