Hello,
How I can treat white spots on the bark and black spots on the leaves of a red maple tree ?
Thanks
Aren’t you lucky to have several native maples on your property. I will answer your query in two parts.
Although the details on your photo are a little difficult to see, according to the University of Minnesota what could be on your tree are harmless lichens. Lichens are made up of algae and bacteria and will do no harm to your trees. For further information please see this link: Non harmful tree conditions
With regards to the black spots on the leaves which I don’t believe are pictured in the photo, the first thought that came to mind is tar spot. This disease is quite common in maples and once you start looking for it, you will notice just how many trees are affected by it. The spots begin slowly as a discoloration on the leaf and then gradually become darker and slightly raised. Although it does not do any real damage to the tree, it is unsightly. The spores of the fungus will overwinter on the fallen leaves, so while we normally would encourage leaving the leaves to feed your garden, in this case I would recommend bagging them up and putting them in the garbage to prevent reinfection and even spreading further to other nearby trees.
More information on Tar spot.
Good luck!
June 2, 2024