206 



FU^^'GI AXD FUXGICIDES 



that single cubic inch of smut would contain more 

 than 15,000,000,000 of them. The dry spores are glo- 

 bose, and brownish-black, with the outer surface thickly 

 studded with elevated points. The method of germina- 

 tion and of the formation of spoiidia is well illustrated 

 at Fig. 85. The mycelium is whitish, and the tips of 

 the threads are able to penetrate the cells of the corn 

 plant. The cells are also penetrated by the liaiistoriay 

 or suckers from along the mycelial threads. 



Treatment. — In the light of our present knowl- 

 edge, measures looking toward the lessening of loss from 

 smut must be largely of a preventive nature. As Pro- 

 fessor Kellerman has pointed out, we must know the 

 mode of infection of the corn plant by smut before we 

 can be sure of the most rational remedy. The fact, 

 however, that smut thrown or left upon the ground pro- 

 duces the disease in succeeding crops, and the apparent 

 probability that infection may be brought about by the 

 distribution of the spores, or sporidia, in manure, indi- 

 cate (1) that rotation of crops should be practiced, and 

 (2) that as much of the smut as possible should be 

 destroyed before it comes to maturity. It will pay the 

 careful farmer to cut out and burn, or bury, the smut 

 balls before the membrane covering them * bursts and 

 allows the spores to escape. At the time of husking, all 

 smut masses that have escaped detection should also be 

 disposed of. '' Where domestic animals are allowed to 

 eat smut in the field they become the carriers of the 

 spores, and their droppings, filled with the still living 

 spores, become the centers of infection. IsTo animal 

 should be permitted to eat smutted corn, even though 

 the owner be convinced of its liarmlessness to the animal 

 itself. The harm lies in the distribution of the spores, 

 which are little, if at all injured, by passing through the 

 alimentary canals of animals. '' (Bessey.) 



The soaking of seed corn in copper sulphate solu- 

 tions to destroy the adhering smut spores, has frequently 



