SPECIES OF IMPORTANCE OR SPECIAL INTEREST 301 



Species of importance or special interest. In studies of 

 smuts primary consideration has always been given to those in- 

 volving cereals. These include Ustilago zeae on corn, U. avenae 

 and U. levis on oats, U. tritici, Tilletia tritici, and T. levis on 

 wheat, Ustilago niida and U. hordei on barley, Sphacelotheca 

 sorghi and S. reiliana on sorghum, Urocystis occulta on rye, 

 and Tilletia horrida on rice. 



The bunts of wheat caused by Tilletia tritici and T. levis, com- 

 prehensively treated by Holton and Heald (1941), are believed 

 to occasion greater losses than those caused by any other smuts. 

 They not only transform the smutted kernel into a foetid mass 

 of spores, but also the spores are liberated in threshing operations 

 and may lodge on normal grains. In consequence of the 

 pungency of triethylamine, to which the odor is due, the entire 

 mass of threshed grain may be malodorous. In years when bunt 

 reaches epidemic proportions, it has been known to cause ex- 

 plosions and disastrous fires. Cardiff et al. (1914) noted that 

 static electricity, generated bv moving parts of the separator that 

 are not grounded, may ignite the inflammable smut spores to 

 initiate the explosions. 



Tilletia horrida on rice is another of the species that com- 

 pletely destroys the ovaries. It appears to have been imported 

 into the United States about 1898 on seed rice and was at first 

 thought by Anderson (1899) to be identical with T. corona, at- 

 tacking various species of Leersia. Apparently in the course of 

 his studies of rice smut Anderson found that rice and wheat can 

 be puffed in much the same manner as popcorn. 



It still remains doubtful whether the so-called T. sphagni is a 

 smut fungus, although Nawaschin (1890) concluded that the 

 microspores interspersed in capsules with the spores of Sphag- 

 num were those of this smut. 



The chlamydospores of Entylovm ellisii on spinach germinate 

 within the host tissues, and the promycelia emerge in tufts 

 through the stomata. They may be formed in such profusion as 

 to make whitish patches. It is readily understandable that the 

 sporidia may be mistaken for conidia of some imperfect fungus, 

 such as a species of Cylindrosporium, Gloeosporium, or Fusidium. 



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