254 



■ease is too well known to need description. The unsightly 

 pustular masses filled with black powder are only the fruit- 

 ing portion of the fungus. They usually occur on the ears 

 but are occasionally seen on the tassels or on the leaves. 

 Under the microscope each particle of the black smutty 

 powder is found to be a minute brown ball-like spore cov- 

 ered with little spines. The mycelium or vegetative portion 

 of the fungus grows entirely within the corn plant. It con- 

 sists of delicate colorless threads which penetrate the tis- 

 sues of the corn plant and draw its nourishment from it. 

 They cannot be seen without the use of a microscope. 



Corn smut is widely distributed. Probably no field can 

 be found entirely free from it. Farmers are so accustomed 

 to seeing it that but little thought is given to the loss it 

 causes. It is true that in individual cases this is not great; 

 it does not sweep through a field destroying an entire crop 

 as is the case with some diseases, but the aggregate loss 

 it occasions is quite large ; cattle are sometimes killed by 

 pasturing in badly smutted stalk fields. 



The smuts of the small grains can now be quite success- 

 fully controlled by treating the seed. Ho far no treatment 

 has been found that is of the least use for corn smut. It 

 is sometimes recommended to go through the fields and re- 

 move th3 diseased stalks as soon as they can be detected 

 before the spores ripen. If this should be done persist- 

 ently by all the farmers in a neighborhood, it would doubt- 

 less materially reduce the loss from the disease in subse- 

 quent crops. At present no other remedy can be suggested. 



OATS. 



Oat Smut. — Like corn smut this is a widely occurring 

 disease. It is caused by a similar fungus {Usfilago avenae). 

 The spore masses are much smaller than in corn smut, and 

 the single spores are slightly smaller and smoother. The 

 smutted heads of course go through the thresher with the 

 rest, so that the dusty smut spores are well mixed with the 

 grain. When such smutty seed is planted the following 



