314 Diseases of Economic Plants 



Arizona in 1915 on wheat; since then, in the western United 

 States, on barley, rye, and many wild grasses. On barley it 

 has appeared as far east as South Dakota. 



Bunt, Stinking-smut ^-^ (Tilletia Icevis Kiihn, Tilletia tritici 

 (Bjerk.) Wint.). — Tilletia tritici causes heavy losses in the 

 Northwest, T. Iwvis in the eastern United States. Where 

 both occur the first is known as ''low smut," the second as 

 "high smut" from their respective habits. This smut (for 

 practical purposes the two may be considered as one) is 

 readily distinguished from loose-smut by the fact that it 

 attacks only the grain, not the inclosing chaff. The head 

 therefore remains of much more nearly normal appearance, 

 and it is often not until the glumes have been opened, and 

 their contents examined, that the presence of the smut mass is 

 detected, covered with its membrane, and resembling the 

 wheat grain in size and shape. It may be recognized by an 

 expert observer by its peculiar, disagreeable, penetrating 

 odor, and by the deeper green color of the diseased heads. 

 The smut masses are often so firm as to remain unbroken 

 through threshing, but they may be recognized among the 

 grains by their darker color, greater plumpness, absence 

 of groove and germ, and finally by crushing them and lib- 

 erating the black spores. 



The disease is particularly destructive, since its presence 

 signifies not only loss of grain due to replacement by smut, 

 but also loss in value to the good wheat, which may be 

 largely depreciated in price by the presence of the bunt. 

 Often bunted wheat is worthless for milling purposes and 

 even for cattle feed. Bunt constitutes, for these reasons, 

 one of the worst smuts in the world. Strong fanning re- 

 moves part of the smutted grains, but troublesome wash- 

 ing processes must be employed to remove them all. and even 

 then the results are not entirely satisfactory. The annual 

 loss from bunt in the United States is about 25,000,000 bu., 

 to which should be added the frequent loss from explosion 

 of threshing machines, estimated at $1,000,000 in two years, 

 due to the oily combustible spores. Where low smut alone is 



