White spots on my sugar maple trees - Ask Extension
Yesterday, I noticed pigeon tremex wasps on my sugar maples in my yard. In doing research on these wasps, I learned that they usually deposited their ...
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White spots on my sugar maple trees #146026
Asked August 08, 2013, 11:40 AM EDT
Yesterday, I noticed pigeon tremex wasps on my sugar maples in my yard. In doing research on these wasps, I learned that they usually deposited their eggs in sick/dying/dead trees. My sugar maples aren't dead, but there were several of these insects on my trees. So I started looking more closely at my trees and noticed that there are tons of white spots all over my maples, the leaves are wilty/drooping, and I even noticed that a few in our pasture have started loosing entire branches from the maple trees - the leaves dying off. We thought it was due to a bulldozer hitting the tree and killing the tree. But now that I look, I'm worried we might have Verticillium wilt in our sugar maples. Walking around our 13 acres, we noticed that most of ours, and our neighbor's 13 acres as well, all have these white spots (ranging from quarter-sized to softball-sized) all over the trees. Is this something we should be concerned about? How do we go about getting a positive ID? And if this is the case, what do we do? I would be so sad if we lost all of our beautiful sugar maples to this! We produce maple syrup and I'm worried if this will also affect our maple syrup production. Any thoughts/advice/suggestions are welcome! Thank you in advance!
Grand Traverse County Michigan
Expert Response
Hello,
Would it be possible for you to take and send photos to us. I would like to see a photo of the white spots you describe, and an overall photo of one of the trees with wilting/drooping leaves and the wasps.
Thank you.
Would it be possible for you to take and send photos to us. I would like to see a photo of the white spots you describe, and an overall photo of one of the trees with wilting/drooping leaves and the wasps.
Thank you.
These are some of the white spots seen on my trees.
And here are the pigeon tremex wasps we found on the trees along with the unusual fungus seen near them.
Thank you!
- Emily
Thank you!
- Emily
Thank you for the photos; I am not able to determine the cause of the decline for these maple trees. However, the white and green spots in the photos are lichen; these are not at all harmful to trees. For more information about lichens, please review this fact sheet,
Thank you for contacting Ask an Expert.
www.herbarium.usu.edu/fungi/funfacts/lichens.htm
You are correct that these are wood wasps. You probably learned while identifying them online that these wasps are seen only on trees that are already in declining health. So, they are a secondary threat to the tree(s). It would be extremely unusual for the cause of the decline to be verticillium wilt in such a large area; this disease is normally seen in small pockets. Since you have so many trees affected, I would recommend that you send a sample from one of the trees to the Diagnostics Services lab at MSU. There is a fee of about $20 for them to diagnose the cause of the decline. Instructions and a form to submit with a sample may be found at http://www.pestid.msu.edu/Thank you for contacting Ask an Expert.
Thank you, I'll submit a few specimen to the Diagnostics Services Lab at MSU and hopefully we can find out what's going on to my poor trees! To clarify, the lichen I wasn't worried about... but it was the white circular fungus that was concerning. I read, "Along with the eggs, the
white rot fungus Daedalea unicolor is also introduced. This fungus grows
within the wood ahead of the horntail larvae and is required for their
successful development. Infection of trees with white rot fungus accelerates
decay and further weakens the structure of affected trees." (http://www.ext.colostate.edu/pubs/insect/05604.html) I wasn't sure if this is what I was seeing or not?
Unfortunately, I wasn't able to enlarge your photo with clarity so I'm not positive if that is the white rot fungus or not. What you can do for verification is include a note in your sample submission to the Diagnostics lab, and after you've submitted the sample, send the photos via email directly to Howard Russell, entymologist at <personal data hidden>.
