DISEASES. 149 



head that has been moistened will bear from 

 30,000 to 50,000.* 



These spores are really seeds, and if the right 

 degree of moisture is supplied they germinate 

 in a few hours and produce very minute, thread- 

 like plants, from which soon develop "sporids." 

 The wind may blow these latter upon a young 

 corn plant, in which case they may grow into 

 its vegetable flesh and develop to a remarkable 

 degree and eventually break out in the com- 

 mon form of smut. 



This disease is distributed through the agency 

 of the smut, and the more the spores are scat- 

 tered about the more prevalent it may become. 

 It is abundant all over the United States and 

 in the corn-growing parts of Europe. While 

 considerable damage may occur from this fun- 

 gus the extent of this is not generally appreci- 

 ated by corn growers. Bessey states f that in 

 Iowa he saw a piece of land the crop of which 

 ''fully 66 per cent had been destroyed." This, 

 however, is an unusually severe case. Prof. W. 

 H. Brewer says: J "I have never seen a field 

 which has been injured to the extent of one per 



* Bessey: Bulletin 11, Nebraska agricultural experiment 

 station, Dec. 18, 1889, p. 29. 



t Bulletin 11, Nebraska agricultural experiment station. 



J Tenth census of the United States, "Vol. Ill, report on 

 the cereal production of the United States, p. 107. 



