Maple disease?

Asked October 3, 2018, 9:31 AM EDT

I have maple trees in my yard. Not sure which kind. Palm size leaves and growth of about 30 ft with a beautiful umbrella like canopy. I'm seeing browning on the leaves and also large brown spots on the leaves. What is this? Do I need to be worried. I have pics of needed...

Berrien County Michigan

1 Response

It appears that your tree is infected with maple anthracnose, a fairly common fungal leaf disease in cool, wet weather. It appears your leaves are also hosting another fungal disease called tar spot, which is very common in our area in late summer and fall. Neither of these will kill your tree (which is probably a Norway maple considering the size of the leaves). They impact the leaves, not the tree.

Considering the lateness of the season, the size of your tree, and the fact that these diseases are not fatal, spraying is ineffective (and expensive).

Because the fungal spores from both diseases can overwinter on the fallen leaves and re-infect next year's leaves, it is important that you rake up and destroy the leaves from your maple tree this autumn. Bear in mind that spores are also carried on the wind, so it is still possible to have a re-infection next year if we have a cool, rainy period and your neighbors have the disease.

These leaf diseases can be unsightly, but they pose no serious threat to your tree. The links below will give you the information you need: