Trees will abort their developing fruit if they are under stress of have produced too much to maintain. This is called 'June drop' in apples and other fruit trees and some level is normal and expected. When we have droughts or other stressors on trees, they can lose nearly all of their fruit in an attempt to save energy and water. It could be that the honey locusts in your area are a little drought stressed or produced too much fruit this spring. As long as the tree itself otherwise looks healthy, I would not be too concerned.