We need photos, please. Could be tar spot, purple eye, leaf galls.........

Those are galls from caused by the maple bladder gall mite. The mites, too small to be visible to the naked eye, have created overgrowth of maple tissue in order to create a reproduction haven. The galls are considered a non-pest, just an aesthetic distraction.

The newly hatched mites overwinter on the trunk and branches of their host plant and if the galls become truly numerous, an application or two of properly diluted horticultural oil sprayed thoroughly on the bark in the winter just before bud break may be helpful. There is absolutely nothing you can do during the growing season to make them go away.

Thank you! I was worried that the tree would die

Only just seen this post. I answered on your other incomplete one. Came to the same conclusion.

i would RARELY suggest treatment on a deciduous tree.. after all.. the leaves will fall off later in the year...

99% of the leaf is still functioning.. converting sunshine into energy.. so whats the problem... there really isnt one ...

this is one of those plagues that happens every ten years or so .. contact your COUNTY extension office.. to see if its a county wide thing... let us know if they have anything interesting to say about it...

just dont get conned by some snake oil salesman.. that wants to fix the problem for a grand or two.. the tree is not threatened in the least.. its what might be called a cosmetic issue ...

i wish i still drank coffee.. because i mite have the gall to come up with a pun.. wait.. i did it without... lol

ken

ken, your comment about deciduous trees rarely requiring treatment is misleading. In this particular case, for example. And for many ornamentals. And for nearly all fruit trees. Affected leaves may fall but more often than not, pest eggs or larvae and fungal propagules overwinter in the nooks and crannies of the bark and branches. As in this particular case, THE time to take action is in the dormant season when the leaves are gone.

Leaf galls may be cosmetic rather than functional but if the mite population becomes very large, then these galls become a health issue for the tree without a doubt. If someone can curtail the numbers organically with applications of a simple horticultural oil, that’s a good thing, right?