Q.Sour Cherry Tree Leave Are Getting Skeletonized And Falling Off.n
Third year in a row. Noticing little black hard droppings on patio under tree. Massive fruit all 3 years, but then leaves start dropping off immediately after fruiting.

Certified GKH Gardening Expert
There are quite a few pests that will cause this. A broad spectrum insecticide should take care of the issue. Here are some articles that will help:
https://www.gardeningknowhow.com/plant-problems/pests/insects/skeletonized-plant-leaves.htm
https://www.gardeningknowhow.com/plant-problems/pests/pesticides