VEGETABLE AND FIELD CROPS 



287 



Blotches ^ appear upon the leaves, first as small, moist, 



watery areas, associated with slight local wilting, followed 



soon by the appearance upon either side of the leaf of very 



small brown acervuli. The 



spots then change to gray and 



dry up. The disease spreads 



rapidly from plant to plant 



and is very destructive both 



under glass and in the open, 



rendering the plant unfit for 



use. 



White smut (Entyloma EI- 

 lisii Halst.). — The attacked 

 plants are unmarketable, due 

 to lack of uniform green color 

 and the presence of pale 

 bleached spots upon the foli- 

 age. These spots are not 

 definitely Hmited, nor does 

 their tissue die as it does in 

 the case of other spinach leaf 

 spots. 



Black mold (Cladospornmi 

 macrocar'pum Preuss. ) . — The 

 black mold develops especially 



upon old leaves, and renders the plant unsalable. The 

 spots are distinguishable from all other spinach spot dis- 

 eases by their irregularity, indefiniteness, and color. 



General. — To control all the above spinach diseases, it 

 is well to burn diseased refuse, practice rotation, and 



1 Halsted, B. D., N..I. Agr. Exp. Sta. Bui. 70, July, 1890. 



Fig. 125. — Spinach leaf spotted by 

 heterosporiose. After Reed. 



