Norway Maple Leaves

(Question)

We live in Mississauga and have a 10 year old Norway maple tree that is dropping its leaves prematurely. In the last 3 days, it has dropped at least 50 leaves. The leaves are completely healthy except on the stem ends are black marks that appear to be “burn” marks. I have attached a picture.

Please advise what the problem might be and any action that we should take to assist the tree.

Thank you

(Answer)

This is a difficult question to answer.  Leaf drop in the spring is an indication that all is not well with your tree.  At first one might think the premature leaf drop of your Norway maple is related to this year’s peculiar weather patterns because the leaves themselves are not damaged in any way.  If this is the case then next year the tree should be ok.

However, the leaf stem in your photo appears to be a black colour. This may be an indication that the tree has become infected with a sooty mold caused by a variety of fungi.  Leaves can drop with this disease.  It can often occur after an aphid infestation. High populations of aphids can cause leaf drop. For signs of aphids look for a sticky substance on the lower side of the leaves. Unfortunately spraying with chemicals is not an option due to Ontario’s Pesticide Act. Therefore, sanitation around the tree is important.  Rake up the leaves when they fall and dispose of so as not to re-infect. Do not use as compost. Hopefully the tree will recover.

If you do not see a complete recovery next year then you may need the services of an arborist.