256 FUNDAMENTALS OF AGRICULTURE. 



Loose Smut of Wheat affects the heads in the same 

 way as the loose smut of oats. Its spores are shed 

 earlier, however, and at harvest time only the stems 

 of smutted heads remain. Some of the spores are car- 

 ried by the wind to the later opening flowers, and the 

 fungus enters the forming grains. These grains ripen 

 normally, the mycelium becoming dormant. When 

 they sprout, the mycelium begins to grow with the seed- 

 ling wheat, and follows upward in the growing tip with- 

 out giving evidence of its presence until spores are 

 formed in the head. 



The Corn Smut differs from the loose smut of oats 

 and of wheat in being able to infect any soft tissue of 

 its host, in never spreading far from the point of infec- 

 tion, and in maturing its spores a few days after in- 

 fection. These spores may germinate at once, and 

 spread infection through the field; or they may remain 

 alive over winter, and start new infection the next sea- 

 son. The swollen spore masses occur on all above- 

 ground parts of corn. 



How to Control Smuts. When infection takes 

 place only in the seedling stage from spores adhering 

 to the grains, smut can readily be controlled by disin- 

 fecting the seed. Formalin is most frequently used in 

 a strength of one pint to forty gallons of water. The 

 seed may be sprinkled in a pile if shoveled over so that 

 every grain becomes thoroughly wet. The pile must 

 be covered with wet cloths for two hours to prevent 

 evaporation of the formalin. Besides loose smut of 

 oats, stinking smut of wheat or bunt, covered smut of 

 barley, and grain smut of sorghum can be successfully 

 controlled by seed treatment. 



How to Avoid Smut. When infection takes place 

 at the time of flowering, and the mycelium is dormant 

 inside the seed, disinfection is unsatisfactory. To 

 reach effectively and destroy the mycelium severe treat- 

 ment is required, and the grain is injured for seeding 

 purposes. The only way of avoiding smut in such 

 cases is to secure seed from a smut-free locality, or 



