530 THE SMALL GRAINS 



seed for a seed plat (191) and sowing the large field with 

 seed taken only from the seed plat. 



571. Effect of time of seeding. The time of seeding 

 of spring wheat and barley had no effect on loose smuts in 

 experiments conducted at the Minnesota Experiment 

 Station. Very late sowing of winter barley at Amarillo, 

 Texas, however, resulted in almost no smut, while sowing 

 at the ordinary time or earlier in the season resulted in a 

 large amount of smut. This variation was probably due 

 to a difference- in optimum temperature for the internal 

 smut and the seed germination. 



572. Smut-resistance. Varietal differences in sus- 

 ceptibility to loose smuts have been observed in both 

 wheat and barley, but no immunity of particular value 

 has been discovered, except that Manns reports his in- 

 ability to infect Poole wheat with this smut because of 

 " this variety's resistant qualities to the smut disease." 

 The Burt and the Early Ripe oats are practically immune 

 from loose smut of oats. In Australia, Medeah, Florence, 

 and Genoa, wheat varieties are considered to be some- 

 what resistant to wheat bunt (206). 



MISCELLANEOUS CEREAL DISEASES 



In recent years some other diseases of cereals have 

 been found to be of considerable importance which were 

 formerly little studied in this country. Still others are 

 better known, but are of local or occasional interest. 

 These are usually caused by those plant parasites known 

 as imperfect fungi, because of the fact that in many cases 

 their complete life histories are not known. 



573. Wheat scab (Gibberella saubinettii, Sacc.). This 

 is the best known of the minor cereal diseases to the or- 



