We are in a drought. The trees (honey Locust) turned yellow and the leaves are falling like rain. They are dry and brittle when they fall. * Is it caused by a drought or is this an insect and if so what kind and * how to deal with it. *Will this kill the trees or is it in a survial mode. *Will it dye or come back if we have a good winter. **Should I be worried? These trees are over 35 yrs old.