Diseases of the Sugar Beet, 



359 



since soaking the seed is often resorted to in practice. In gen- 

 eral, even the strong solutions of copper sulfate gave slightly 

 better results than the water ; and 

 germination was often slightly 

 hastened. In a preliminary test, 

 the germination was very mark- 

 edly in favor of the copper treated 

 seed ; but since the conditions 

 were abnormally close and moist, 

 the exclusion of bacteria by the 

 copper solution might have caused 

 the apparently excessive -benefit. 

 • It remains to be determined, 

 however, if it is desirable to treat 

 the seed for the prevention of the 

 leaf -spot. 



III. 



Beet Scab (Oospora scabies 

 Thaxter). 



a. 



Appearance of the Disease. 



The smooth surface of the beet 

 root may often be disfigured by 

 wart}^ or scabb}^ excresences. 

 The texture of these injuries is 

 somewhat corky or spongy, and 

 the larger diseased areas will show 

 that the injury is not entirely su- 

 perficial, but to some extent alters 

 the tissues immediately underly- 

 ing such areas. The frontispiece 

 shows two beets affected in a char- 

 acteristic manner. The disease 

 begins as small irregularities either 

 widely scattered or clustered. In- 

 dividual ones spread in extent, and 

 groups often become united, so that in time it may spread over 

 large areas, or small isolated areas may remain. One often 

 notices a tendency for the scabb}^ spots to be arranged in more or 



62. — Beet scab. 



