218 CORN 



spore. These spores germinate very poorly in water, but grow rap- 

 idly in nutrient solutions such as liquid manure. A well manured 

 soil is favorable for their production. When one of these little con- 

 idia is freed from the stem on which it grows and is carried by the 

 wind, alighting upon an active growing portion of the corn plant, it 

 soon germinates and sends out a thread-like mycelium which pene-, ,j 

 trates the tissues. Generally about two weeks' time intervenes be- 

 tween the period of inoculation and the appearance of smut spores. 

 From this time on growth is very rapid. These smut balls often- ,<i 

 attain a size larger than an ear of corn. Should a smut ball fa.ll to'J 

 the ground and favorable conditions present themselves, the above ; 

 outlined life cycle is repeated. 



It is thought that the early infections come from last year's spores 

 which germinate as soon as favorable conditions are at hand. - The 

 slender threads that are put forth by the conidium when it alights 

 on a growing portion, are colorless and known as the mycelium. They 

 send numerous branches into the cells of the plant, which draw from 

 it nourishment for their own maintenance. These slender threads 

 (the mycelium) develop very rapidly, and soon become a dense, felt- 

 like mass. A little later practically the entire mass is converted into 

 small round spores. 



Corn smut cannot be prevented by soaking the seed in fungicides, 

 as is the case with oat smut and the stinking smut of wheat. This 

 is due to the fact that the infection takes place after the plant begins 

 its growth, and does not result from the spores being present on the 

 seed. The smut of corn resembles the rust of wheat in its mode 

 of attack. If the smut balls are all removed from the stalks and 

 destroyed, the percentage of infection will be greatly decreased. This 

 practice is carried on to some extent by smaller farmers. The ex- 

 pense incurred, however, is usually greater than the loss due to the 

 smut. 



Loss Is In the Ears. 



Experiments carried on at the Kansas Agricultural College go to 

 show that the loss to corn plants attacked by smut is chiefly in the 

 grain, the weights of smutted and clean stalks being practically the 

 same, while the loss in the yield of corn amounts to about one-third, 

 even though the ears themselves are not attacked. 



The following table from the Kansas Agricultural College counts 

 the smutted stalks just as they came regardless of the place of in- 

 fection : 



