198 



FUXGI 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, eno^raved after Kellerman and Swin- 

 gle. The powder soon blows away, 

 leaving the bare chaff and stem, b. 

 This disease is found, to a greater or 

 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 

 raport 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 ^olant to the 

 other. Professor Bessey has shown 

 that part of the heads of given stools 

 of wheat may be affected with loose 

 smut, and part be healthy. 



The Wheat Scab 



Fusisporium culmorum 



This is a peculiar disease which 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 



WHEAT SMUT. 



