CORN OB MAIZE 97 



diseased portion of the stalk. Corn stover affected with smut is 

 thought by many farmers to cause illness to animals to which it is 

 fed. In experiments to determine whether or not the corn smut 

 is the cause of illness among animals, it was fed in comparatively 

 large amounts to groups of animals, and the results carefully 

 noted. In no case did the animals show any effects from the 

 feeding of the smut. 



79. Ear-rots. — It is the very general opinion of farmers that 

 the ear-rots of corn are caused by adverse weather conditions. 

 Careful studies of these diseases wiU show that they are caused 

 by a fungous growth, and while the weather conditions may be 

 favorable or unfavorable for the growth of fungus, it is not the 

 direct cause of the trouble. There are several kinds of ear-rots, 

 but their appearance on the ear is so similar as to be generally 

 regarded as one form. The most common is the Diplodia, or 

 dry rot, which attacks the husks, kernels, and the cob of the corn, 

 causing the husks to stick to the ear. The ear becomes dark in 

 color, often nearly black, except for the white mold-like growth 

 which is abundant between the rows of kernels. It is a common 

 practice at husking time to throw the ears of corn affected with 

 this disease on the ground. This practice is the means of spread- 

 ing the disease and giving the best opportunity for its being 

 carried over the winter. The spores from the ears thrown on the 

 ground spread to the corn stalks, where they make a slight growth. 

 The next year the spores are spread by the wind to the growing 

 corn, where, if weather conditions are favorable, they develop 

 into the disease. The Illinois Experiment Station has found 

 that stalks, after having been plowed under for two years, still 

 retain the spores that will germinate under favorable conditions. 

 This station, therefore, recommends that diseased ears be de- 

 stroyed. It is also a good plan to burn the stalks on a field that is 

 badly affected. It was found, further, that corn grown in a 

 rotation was not so badly affected as that grown under a con- 

 tinuous cropping system. 



Beside the dry rot, there are several species of fusarium that 

 attack the ear in much the same way. The casual observer would 

 not be able to distinguish them from the dry rot. 



80. Rust and bacterial diseases. — Corn is affected by 

 several kinds of leaf rusts and bacterial diseases, but the damage 

 done is usually small. 



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