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, which fall prematurely, or by similar spots upon 

 the young green shoots. In seasons favorable to bhght 

 much of the terminal growth is killed and the succeeding crop 

 is thereby reduced. 



Fig. 100. — Dact3rial b:i;ht of walnvitj. .-^rter 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 salidscaprce (Pers.) Wint.). — Of 

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



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



