22 



Levi Otto Gratz 



A large proportion of these seedlings developed typical wire. stem. This 

 demonstrated that the fungus was still in the soil and in an active condition. 

 The tubers were harvested when they were from one to two inches in 

 diameter. Very few definite lesions vvere produced even by the strains 

 from potatoes, probably because of the unfavorably low temperature. 

 The striking difference was in the occurrence of the sclerotia on both the 

 old seed pieces and the new tubers, many sclerotia having been produced 

 by the strains from potatoes, but none by the cabbage strain in any in- 

 stance (table 8). None of the lesions reported in the table were very large, 



TABLE 8. 



Results of Inoculating Potatoes with Different Strains of 

 corticium vagum 



Num- 

 ber of 

 pots 



10 

 10 

 10 

 10 

 10 

 10 

 10 

 10 

 10 

 10 

 10 

 10 

 10 

 10 

 10 

 40 

 10 



10 



Strains 



Tnknown 



Potato 



Salvia 



Potato , 



Lettuce 



Pepper 



Potato 



Eggplant 



Pea 



Bamboo 



Potato 



Tomato 



Unknown 



Unknown 



Grass 



Cabbage 



Cabbage (stems inoculated 



twice) 



Controls 



Number 

 of new 

 tubers 



14 

 16f 

 14 

 19 

 12 

 18 

 13t 

 15 

 12 

 15 

 15 

 19 

 15 

 16 

 15 

 100 



25 

 21 



* +, an occasional sclerotium, or very slight lesion; + +, few sclerotia, or rather definite lesions; + + + , 

 numerous sclerotia, or deep lesions; + + + +, very many sclerotia, or several deep lesions. 



t Stems of most of the tubers were covered with the weblike mycelial mat characteristic of Corticium 

 vagum. 



although all were typical. It is to be noted that every potato strain 

 produced lesions, even though few in number, while only four of the other 

 strains did so. Only the potato strains produced sclerotia on the new 

 tubers and on the roots. With one or two exceptions the potato strains 

 produced the most and the largest sclerotia on the cut surfaces of the seed 

 pieces. The cabbage, tomato, grass, bamboo, and lettuce strains produced 

 no signs nor symptoms of the disease on either the roots, the stems, or 

 the tubers. 



