Elm Yellows

 Elm Yellows  is a serious systemic disease of American, red, and winged elm trees.  It is caused by an MLO or Mycoplasma like organism.  The MLO is a bacterium that lacks a cell wall and can assume a variety of shapes.  The disease is spread by leaf hoppers and root grafting.  Symptoms begin in mid to late summer with chlorosis and drooping of leaves.  The symptoms can appear abruptly and in some cases trees wilt and die quickly.  The inner bark yellows then develops tan flecks and eventually dies.  If the inner bark is exposed there is a smell of wintergreen.  There is no cure for Elm Yellows.