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Question from Dave, UT (received 8/26/20) -
Today I had a tree trimming company come out and look at my Maple tree. I think he is an arborist by training and education. I told him that I had treated the tree with Bayer insect treatment this spring and a second treatment in late May. He saw no evidence of bore holes in the tree. He thinks it may be a fungus of some type perhaps Sylibus?(Probably not the correct spelling or perhaps word). Any way he said it originated in the ground, was a fungus and ran up the cannulas and plugged it off the pores, which killed off the branches quite slowly. What if I used powdered bleach, like for a hot tub or swimming pool, and have the roots take it up, would that work? Let me know if removal is the only remedy.
My questions to you are:
- Is there a cure for this if what is ailing the tree if it is a fungus?
- He said the cost of looking at the soil for evidence of the fungus will cost $200 to $250. Is this a realistic cost?
- Is there anything I can do to fix the problem?
Answer from Dr. Mike Kuhns, USU Extension Forester and Professor (sent 8/28/20) -
David,
Your tree looks like a Norway maple, and it has a large limb that has died. Also, in 2 of the pictures you can see a fairly large pruning wound from a cut that was made about a year ago near the point of attachment of the dead limb. In my experience with Norway maples, significant canopy dieback is common as the trees get older and less vigorous and especially if significant pruning is done and especially if it is done in the summer and if that pruning opens up the tree’s canopy so that it gets lots more sun than in the past. So this will keep happening, and the only thing that can be done about it is to prune in the winter or early spring and prune branches early so that you are never cutting branches bigger than about 2” in diameter.
As for what you have done or are thinking about doing, it is best to deal with an ISA Certified Arborist. You should only treat trees for known problems and with appropriate materials and treatments. Your insecticide treatments likely have no effect, other than maybe killing some aphids, which, though they can be a nuisance in Norway maples, I do not think that they are worth treating for. There are no significant borers that attack this species. Though there may be a stem canker fungus that is involved with the pruning-related dieback, I have not heard of one and the way he/she describe the fungus, originating in the ground, running up the cannulas and plugged it off the pores, and killing off the branches slowly, sounds bogus. Needless to say, paying $200-250 to look for it in the soil will not do any good, but it won’t be the only expense. He will find something and will want to treat it for lots more money. Also, do not put powdered bleach in the soil; it will harm or kill the tree.
It seems to me that the is enough live canopy that you do not have to treat the tree or get rid of it. You should be able to have the dead wood pruned out every 2 or 3 years using my advice above.