266 



Science of Plant Life 



the alternate host plants are the wild and cultivated goose- 

 berries and currants. Another common rust is frequently seen 

 on raspberry and blackberry bushes along 

 roadsides ; it colors the imder sides of the 

 leaves with its bright, orange-red spores. 

 The smuts. The smuts of oats, wheat, 

 barley, and corn often greatly reduce the 

 yield of these plants. But since their 

 Hfe histories are known, it is coinpara- 

 tively easy to control them. The smut 

 fungi generally are carried over from one 

 year to the next, on or in the grain, and 

 they may live over winter in the soil. 

 When the grain is plantisd, the smut 

 spores germinate and infect the yoimg 

 seedlings. The smut plant lives inside 

 the host, and its presence becomes ap- 

 parent only when the black spores of 

 the fungus appear, usually in the grain. 

 Fig. 157. A normal and In some cases the walls of the grain are 

 smutted flower duster of destroyed and the spores are scattered 



oats. . 



by the wmd. 

 All smuts of the small grains may be prevented from 

 germinating by soaking the seed in hot water for a short time 

 before planting. It is easier, however, to wash the grain with 

 a weak solution of formalin, and this treatment is effective 

 in preventing the growth of those smuts whose spores are 

 carried over the winter on seed. Detailed information con- 

 cerning seed treatment for the prevention of the several 

 kinds of smuts may be obtained from State Agricultural Ex- 

 periment Stations. The corn smut is controlled by removing 



