pink dogwood with mildew
What causes a pink dogwood to have mildew, and is it ok? Six years old located in total sun.
You don't describe what part of the tree is infected, or the appearance of the mildew, so I'm going to guess your tree has powdery mildew, which is probably the most common. This article tells you more about this disease: https://www.gardeningknowhow.com/plant-problems/disease/get-the-cure-for-powdery-mildew.htm
You could call the local Extension Service https://www.gardeningknowhow.com/extension-search/
to ask about recommended fungicides in your area.
But you have another problem here. Dogwood are not normally troubled by powdery mildew, unless they are stressed and weakened. Since you say your tree is in full sun, I'm speculating that this is starting to affect the tree, since they prefer some shade. This article tells you more about dogwood: https://www.gardeningknowhow.com/ornamental/trees/dogwood/caring-dogwood-trees.htm
You can move it, or have it moved, if you care to.