CEREAL PESTS PARASITIC FUNGI 513 



and U. S. C. I. Nos. 1522, 1524, and 1526 emmers, lumillo, 

 Kubanka (C. I. No. 2094), and Arnautka durums, and a 

 variety of einkorn (C. I. No. 2433) (Fig. 157). A few 

 hybrids also have been produced of rust-resistant durums 

 with varieties thought to be better milling wheats, which 

 in the tests so far made appear very promising. Milling 

 and baking tests with some of these show them to be of 

 good quality. 



Rust-resistance varies greatly geographically, and 

 depends also upon the kind of rust. Varieties resistant 

 in one locality may not be so in another. Varieties that 

 escape rust by ripening early must not be confused with 

 rust-resistant varieties. 



CEREAL SMUT DISEASES 



For a long time no distinction was made between rusts 

 and smuts, and both these, as well as some other parasitic 

 fungi, were referred to as mildews or blights. Finally, 

 Tull in 1733 pointed out specifically the bunt of wheat, 

 saying, " Smuttiness is when the grains of wheat instead 

 of flour are full of a black stinking powder." Tillet, 

 over twenty years later, distinguished the two types of 

 wheat smut, describing one under the name " la carie " 

 and the other as " le charbon." 



559. Bunt or stinking smut of wheat (Tilletia tritici, 

 Wint., and T. fattens, Trel.). This is the most important 

 economically of all the cereal smuts. Brefeld made the 

 most exhaustive study of it. He grew it in his Nahrlosung 

 or artificial culture, and worked out the details of its 

 morphology and development. The 2 species of bunt 

 differ in the fact that the one ( Tilletia fcetens) has smooth 

 resting-spores and the other has reticulated spores. 



2L 



