198 



PfXGI AND FUXGICIDES 



The Loose Smut 



Ustilago tritici 



The loose smut of wheat is at once distinguislied 

 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, 

 leaving the bare chaff and stem, b. 

 This disease is found, to a greater or 

 less extent, wherever wheat is sfrown, 

 but is seldom as destructive as the 

 bunt. Xo successful method of com- 

 bating it has yet been found. A good 

 »vVf^/ iL\At< discussion of it occurs in the second 



report of the Kansas Experiment 8ta- ■ 

 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 

 smut, and part be healthy. 



The Wheat Scab 



Fusisporium culmoinim 



This is a peculiar disease which attacks the heads 

 and kernels of wheat. It is usuallv first noticed iust as 

 the heads are beginning to turn, when an examination of 

 infested fields shows that with a jiortion of the heads the 



a 



WHEAT SMUT. 



