Can anyone Identify this foliar issue. It is on approximately 40% of the foliage on a 100 year old maple that has been topped about 15 years ago. The foliage started this year looking very "wilted" and then began to develop this browning/spotting on the leaves. Only a few hours after removing the foliage it had already begun to wilt. The majority of the "scorching" appears on the outer edges of the leafs. I did also notice a minor aphid problem on the leafs as well.
It looks like leaf scorch, which was my original thought, but looking at the verticillium wilt photos of the sugar maple, do you think verticillium wilt could be causing a scorch look? Does anyone think soil testing or foliar testing would be worth it?
I see some summer blighting of bigleaf maple branches in this area, so it seems verticillium could be possible in your case. If that is what you have then there should at some point be blocking of conductive tissue in affected branches, with subsequent blighting (collapse and shriveling). Presumably the pertinent page at above link talks about how you can see the fungal darkening of the conductive tissue when verticillium is present in the stems. If you see that then you don't have to do any testing to find out it is verticillium. When I got what appeared to be verticillium in what was before then healthy, spontaneous vine maple seedlings it was after I bought some "black dirt" and placed it beneath them. Importation of contaminated soil is supposed to be a primary cause of infestation of previously clean sites.
