Cereals 275 



Wheat Rye Oats Barley 

 Copper sulfate 



10 minutes + + + tr 



Long time + + + + + + 



Hot water 



133° 12 minutes + + + + + + tr 



101-115° 3 hours tr tr 



Modifietl 



129° 10 minutes ++ tr 



The Seed Plat. — A good, clean, well-cultivated piece of 

 land should be selected for raising seed. The plat should be 

 large enough to provide at least twice as much grain as will be 

 necessary for farm seed the following year in order to allow 

 for loss in cleaning and selecting. This seed plat should not lie 

 near fields of smutted crops of the same cereals, nor should 

 it be so located that the prevailing winds at flowering time 

 can carry spores to the seed plat from a neighboring field 

 of the same grain. This isolation is absolutely necessary. 

 A strip of wood, a cornfield, or a large meadow is a valuable 

 protection. In this plat should be planted seed treated by 

 the hot-water methods. The seed plat may be maintained 

 from year to year, as long as any smut is present in the grain 

 fields. 



Cereal Rusts in General 



328 



The rusts constitute a complex, intricate, difficult, but 

 interesting group of diseases. It is said that the "average 

 annual loss from rust throughout the United States far 

 exceeds that due to any other enemy, insect or fungous, 

 and often equals those from all others combined." 



The black-stem-rust alone in the United States and 

 Canada in 1916 was estimated to have caused a loss of about 

 280,000,000 bushels of wheat and additional loss on oats, 

 barley, and rye. 



The rusts in their most complete form exhibit three dis- 

 tinct stages (cf. p. 150). The spring stage, or cluster-cup, 

 consists of a group or cluster of very minute, cup-like, spore- 



