450 DISEASES OF ECONOMIC PLANTS 



upon the Pacific coast, where it often causes a loss of 50 

 per cent of the crop. 



It may be recognized as black cankered spots upon the 

 young nuts, Avhich fall prematurely, or by sunilar spots upon 

 the young green shoots. In seasons favorable to blight 

 much of the terminal growth is killed and the succeeding crop 

 is thereby reduced. 



Fig. 196. — Bacterial blight of walnuts. After R. E. Smith. 



Two treatments with Bordeaux mixture, after thorough 

 removal of diseased parts, have been known to prevent 50 

 per cent of the loss. ^ The second spraying should be 

 given when the nuts are firmly set. Care should be taken 

 to select resistant trees for propagation. 



WILLOW 



Tar spot (Rhytismose) . See maple. 



Rust {Melampsora saliciscaprm (Pers.) Wint.). — Of 

 tree rusts this is one of the most abundant, occurring as 



> U.S. Dept. Agr. Yearbook, p. 98, 1904. 



