Magnolia tree disease

Asked July 12, 2018, 9:28 AM EDT

Hi, We our new homeowners and have(had) a beautiful magnolia tree in our front yard. We moved into the house April 2017 and the first spring/summer it was beautiful. This year, we are really struggling with it. Some of the branches have no blooms on it. There are white spots on a lot of the branches, leaves are black and there are tons of bees and other bugs all over the tree. The tree is next to the front door and it has gotten so bad we are unable to use the front door. I have more pictures I can email. Please feel free to call me to discuss if easier.

Dakota County Minnesota magnolia magnolia scale

3 Responses

The tree has been affected by an armored insect called "scale." Magnolia scales deposit honey dew, a sweet waste product, that attracts ants and various flying insects including flies, wasps and bees.

The black residue on the leaves is sooty mold caused by a mold that grows on the honeydew.

This bulletin discusses magnolia scale and how to control them.

Is there anything we can do now to control the problem, or do we need to wait until late August (like it suggests) to do anything?

The scales are covered by protective shells that make them insecticide resistant.
Timing of insecticide application is critical because it must coincide with the brief mobile (crawler) stage of the insect's life cycle. Follow the Wisconsin publication recommendations in this regard.