The leaves on our crape myrtle are turning yellow. We had a problem with japenese beattles so I did a search on how to get rid of them. The post I came across said I needed to use Bifenthrin to kill them at the larvae stage. I've got some stuff called Talstar which contains Bifenthrin that I sprayed the tree with and since then our leaves have started to turn yellow. Can you suggest what I can do to get crape myrtle back to being healthy?