golden colored moss/fungus on my cottonwood tree - Ask Extension
My established dogwood tree has come down with some kind of disease. It has a golden-colored crust on many of the branches and it has killed several ...
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golden colored moss/fungus on my cottonwood tree #644531
Asked June 01, 2020, 6:56 PM EDT
My established dogwood tree has come down with some kind of disease. It has a golden-colored crust on many of the branches and it has killed several of them. I have cut out the dead wood that I could reach but I don't know how to treat this. Is this a common disease in the Willamette Valley and what might it be? The dogwood has been thriving in the same location in my yard for 8 - 10 years. I don't recall seeing this before this spring. Can you give me some advice in how to proceed? Also, can it infect nearby shrubs or plants? Thank you, Analee
Lane County Oregon
Expert Response
First, the orange growth on your tree branches did NOT kill them. It is a lichen (and a lovely one), which is completely harmless. Lichens commonly grow on both living and dead parts of trees, but they don't harm the trees in the slightest.The lichen was on your tree before, you just didn't notice it - it's really obvious now that the branch is dead.
As to how to proceed, you'll need to determine if there is actually anything wrong with your tree, or if it is just naturally losing some branches. You should remove any dead branches - but examine them when you do. Are there any insect holes? Signs of an infection? What does the cut cross-section look like - is there staining, or is it clean? Take pictures of anything you see.
Then examine healthy parts of the tree. Any signs of wilting or flagging? Insect damage? Discolored or distorted leaves? Again, take pictures of what you see.
Also examine the growing conditions. Does the tree get enough water in the summer, or does it get drowned in the winter? Does it get too much or not enough sun? Has there been any work nearby that could have impacted the root system?
Write back with what you find out, and we'll be better able to help you help your tree.
Hi Signe, Just went out and took more pics. Cross-section looks clean, no staining. No insect holes. Definitely LOTS of discolored and distorted leaves with brown spots and inward curling but some of the new growth at the very tips of the branches look healthy. Dead branches are very brittle and they are distributed all the way up and around the tree, not in just one spot. I have never pruned or trimmed the4 tree with the exception of removing one or two low-hanging branches. The growing conditions are pretty stable. Nothing unusual has occurred near the tree base that might have traumatized it. It bloomed nicely this spring but it did seem unusually wet and rainy (but then I always feel that way about mid-may!). By the way, it is a DOGWOOD tree, not a cottonwood. My apologies. Here are some more images. Thanks again for your help. Analee
The leaves could be showing symptoms of anthracnose, which is quite common on dogwoods, and could be causing the dead wood.. Check here to see if the rest of the symptoms match https://pnwhandbooks.org/plantdisease/host-disease/dogwood-cornus-spp-anthracnose
The intensity of an infection can vary depending on weather conditions, but the main preventative is to improve air circulation and remove infected parts and leaves.
The intensity of an infection can vary depending on weather conditions, but the main preventative is to improve air circulation and remove infected parts and leaves.
