48 



ILLINOIS NATURAL HISTORY SURVEY CIRCULAR 46 



First reported in Illinois in 1950, it had spread to all 102 counties 

 of the state by 1959. A detailed description of the disease and 

 suggestions for its control are given in an Illinois Natural His- 

 tory Survey pamphlet entitled "Dutch Elm Disease in Illinois." 









■''»».-v W . ,,. 





Fig. 46. — Foliage on elms that die rapidly from phloem necrosis turns 

 brown and much of it remains attached to the branches. 



