Hello,

Tulip trees, (Liriodendron tulipifera) are fast growing deciduous trees that prefer rich, well-drained soil and full sun. They are subject to many diseases and insect attacks. Read more here: https://www.missouribotanicalgarden.org/PlantFinder/PlantFinderDetails.aspx?taxonid=282514&isprofile=1&basic=tulip

Your tree certainly does have tuliptree scale. Read more about it here: https://entomology.ca.uky.edu/ef435

As the insects feed, they secrete a sticky substance called honeydew which attracts a sooty mold. The sooty mold covers everything in its path, plants, cars and decks. You can remove the soot with a strong spray from a garden hose.

Read here about how to manage scale insects: https://extension.umn.edu/yard-and-garden-insects/scale-insects#using-pesticides-2669961

Scale insects are attracted to trees that are stressed. Perhaps this tree is in a location that is causing it stress. Consider the conditions that it prefers with the location of your tree. Maybe moving it to a different location would work.

A certified arborist will be able to assess the tree. To find an arborist in your area, go to: www.treesaregood.org.