198 



fu]s:gi and fungicides 



The Loose Smut 



Ustilago tritici 



The loose smut of wheat is at once distinguished 

 from the bunt by the fact that the spores are not con- 

 cealed^ so that usually the kernels 

 resemble masses of black powder. 

 Such a head is represented at Fig. 81^ 

 a, engraved after Kellerman and Swin- 

 gle. The powder soon blows away^ 

 leaying the bare chaff and stem, 

 fl W ^^^^^ disease is found, to a greater or 

 // ffii less extent, wherever wheat is grown, 



but is. seldom as destructive as the 

 bunt. 'No successful method of com- 

 bating it has yet been found. A good 

 discussion of it occurs in the second 

 report of the Kansas Experiment Sta- 

 tion, 1889, pp. 261-268. 



It was formerly supposed that the 

 loose smut of oats was the same as that 

 of wheat ; but recent observations indi- 

 cate that the fungi causing the two 

 maladies are different species, and that 

 they cannot pass from one plant to the 

 other. Professor Bessey has shown 

 that part of the heads of given stools 

 ^ "of wheat may be affected with loose 

 WHEAT SMUT. suiut, aud part be healthy. 



The Wheat Scab 



Fusisporimn culmorum 



This is a peculiar disease wliich attacks the heads 

 and kernels of wheat. It is usually first noticed just as 

 the heads are beginning to turn, when an examination of 

 infested fields shows that with a portion of the heads the 



