Q.black mulberry tree
I had recently planted a black mulberry tree. Recently, its leaves started developing black spots then wilting and dying. Why? What should I do?
I'm a bit unsure of what I'm really seeing in this image.
The leaves on your tree seem green and healthy. It does appear you have many branches that are void of leaves.
The ground and soil below looks very dark and I can even see what appears to be a green line in the soil.
Was the ground this color prior to you planting this tree?
Have you watered and used fertilizer? To much fertilizer can burn a plant or newly planted tree and cause the leaves to die and drop.
Is the soil well draining? Or did water pool and sit around the tree? This could cause root rot and the ground to mold. Damp soil conditions also can invite fungus to your garden and plants.
You may want to use a fungicide on the remaining tree to be on the safe side.
Neem Oil is a good treatment.
Here are a few links for you.
http://quod.lib.umich.edu/d/did/did2222.0002.154/--mulberry-tree?rgn=main;view=fulltext
https://www.gardeningknowhow.com/plant-problems/pests/pesticides/neem-oil-uses.htm
https://www.gardeningknowhow.com/ornamental/trees/tgen/watering-newly-planted-tree.htm