Knowledgebase

Disease of maple leaves #138250

Asked July 02, 2013, 4:45 PM EDT

What is this? What should we do for the trees?
This is a significant illness affecting the North and west sides of three contiguous Maple trees that are important for shade in our area.  Do you know what is causing this? ...some of the leaves have turned brown and fallen.  It has only been noted for 8-9 days.
Is there any treatment and what is the prognosis?
Thank you.

Oceana County Michigan

Expert Response

This is not a disease or an illness.  This damage appears to be environmental in nature.  It would be easier if the four images were of different leaves.  What the damage on the one leaf appears to be is possibly leaf bud damage from the late spring freeze or possibly high winds that damaged young, tender leaves. The leaf has a line of damage to the right of the mid-vein. This is not insect damage, either.

If this was a fungal disease, and it is not, there would be a ring around the tan spots.  The tan, dead areas have dried out enough that they are leaving "shot holes."  The dry material just falls out. On this leaf, the damage is minor.  The leaf continues to function normally except for the small amount of dead tissue.

Since this is minor damage and has already happened, there is nothing to do.  The trees are fine.
An Ask Extension Expert Replied July 02, 2013, 10:00 PM EDT
Thank you very much and this is what we obviously want to hear.  However we remain concerned since the extent of the damage seems extensive and therefor we took more photos of the tree today and will attempt to upload them today.  If you still think that the trees will recover, we will be releaved but do not want to miss an opportunity to treat if there is anything that will help.
Thank you.
The Question Asker Replied July 03, 2013, 2:47 PM EDT
This is the problem with sending one picture four times.  I could not see more than one leaf to represent all of your trees.  The damage on those leaves in the wide shot looks completely different from that the leaf picture.  It still does not look like an insect or disease, but now there is the distance problem and the problem of being very blurred. They are tan leaves far away. What percentage of the tree is showing damage?

Has anything gone on around these trees like digging, trenching or any ground work?  Is this close to where a brine tank or sump pump dumps? Did someone pump out the swimming pool contents in that area? Has this area been much wetter than usual to the point of staying squishy or water standing?  Are entre branches of leaves dead or just scattered ones?  As you can guess, this is about discovering what is different this year.
An Ask Extension Expert Replied July 03, 2013, 3:48 PM EDT
I have tried more photos in different lighting last evening.  Nothing has changed at this site in the last year and that is what is so confusing to us.  About a third of each tree is affected and some areas seem completely normal with another very involved.  One tree seems to have a more generalized involvement however and nearly the entire tree is affected.
The Question Asker Replied July 04, 2013, 8:56 AM EDT
Look at the ends of the branches at the newest leaves.  Are the new ones also marked?  If not, the problem has passed.

How long are the green shoots on the ends of the branches?  This is where your new growth came on this year. Leaves are attached to these new twigs. There should be a shoot and not just a couple of leaves.  On the closeup, it appears that the bud scars indicating new growth in previous years are very close together.  That is not good because it indicates the trees are not growing, just existing.  But you are seeing the whole tree, not just a tiny part.

The leaves look like they had anthracnose, fungal disease, that marks leaves in early spring.  It does not continue throughout the season. There is also some bud freezing that happened early.  It should not be on the new leaves. 

If there are no shoots with an inch or more of new growth, this is a big problem.  Measure the shoots and see what you have.  Averaging shoot length on a tree should give you more than four inches of new growth if the trees are healthy.

An Ask Extension Expert Replied July 04, 2013, 11:10 AM EDT

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