We found several leaves that had some type of worm, so we sprayed the tree with insectacide. The tree continues to get worse and seems to be dying by the branch. It doesn't seem to stop. There were no trees in this location previously (new home) and Scott's red bark mulch was used as a weed stop with barrier. The tree has been watered well. Is this a case of verticillium wilt? I have read about it here, but cannot draw a conclusion.