234 AGRICULTURE 



may better kill the smut spores. This treatment costs 



only a cent or two for each bushel of seed. Oat-smut is 



shown in Fig. 159. 



Concealed smut of wheat. The wheat smut which is 

 most injurious is not readily observed. Here, 

 too, the spores of the fungus replace the kernel, 

 but the seed-coats, or kernel coverings, conceal 

 the disease. On crushing one of the diseased 

 " kernels " the spores will be found and the 

 unpleasant odor that arises will not be for- 

 gotten. Concealed smut may be prevented by 

 dipping or soaking the seeds in a solution of 

 bluestone. 



Other diseases. Among other diseases of 

 wheat and oats are several forms of rust, also 

 due to fungi. You may be able to find speci- 

 mens of rust and to compare them with the 

 smuts. 



No treatment has been found to prevent the 

 rusts of grain. Some varieties are more injured 

 by rust than others. Those that ripen early 

 oftenest escape severe injury. If you should 

 find a wheat or oat plant that is free from rust 

 while all others around it are diseased, your 

 Fio. 159. discovery may give rise to a genuine rust-proof 



S-ITTTYOATS variety. 



EXERCISE. When wheat or oats have formed heads, count the 



number of smutted heads on a square foot or square yard of surface. 



Estimate how much the yield will probably be reduced by smut. Are 



the other stems ever stunted on a plant having one diseased head ? Look 



for rusted leaves or stems of wheat or oats. 



