WHEAT 61 



will usually suffer less than late varieties. On low damp 

 land rust is most destructive. Attempts have often been 

 made, with but little success, to breed a rust-resistant 

 variety, that should also be productive and otherwise 

 desirable. Such efforts should be continued. No effec- 

 tive treatment for wheat rust is known. 



Stinking or concealed smut. — This disease changes the 

 grain into a mass of powdery black spores, with offensive 

 smell. It ruins the flour. As the chaff is not changed, the 

 diseased grains may not be noticed. The spores of this 

 fungus are conveyed by the seed wheat, hence the disease 

 may readily be prevented by either of the following treat- 

 ments of the seed wheat : — 



(1) Immerse the seed or thoroughly dampen them with 

 a mixtxire of one ounce of liquid formalin in each three 

 gallons of water ; keep the seed grains damp and the pile 

 covered with cloth for at least a few hours ; then dry and 

 plant the grain. 



(2) Or immerse the seed grain for ten minutes in a solu- 

 tion of one pound of bluestone (copper sulfate) in five 

 gallons of water. 



(3) Or immerse the seed wheat for ten minutes in water 

 kept at about 133° F., then cool the seed promptly by 

 stirring or by dipping the hot grain into cold water. 



Loose smut of wheat (Fig. 21). — This disease is known 

 by the occasional heads that contain no semblance of grains, 

 but only small black masses of powder, consisting of spores, 

 which are microscopic bodies serving the purpose of seed 

 for the fungus that causes this disease. It is rarer than 

 concealed smut, and Uke it, is conveyed by the seed wheat. 

 The fungus causing loose smut of wheat is much less easily 



