TECHNICAL BULLETIN 17 



These organisms were grown on sterilized wheat seed to obtain a 

 large amount of inoculum. At the end of two months, the cultures 

 were practically masses of mycelium and spores. These masses were 

 passed through a meat grinder and the pulp was thoroly mixed with 

 sterilized soil in which the wheat and barley were then planted. The 

 observations on seedling injury at the end of twenty days are sum- 

 marized in Table XIV. 



TABLE XIII 



SUMMARY OF DATA IN TABLE XII 

 Infection classes 



The results on the Lion barley were very sharp. Unfortunately, 

 rats molested some of the pots. In the barley series, however, only the 

 check plants were injured. Three plants were left in each of the three 

 pots. The comparative size of the plants grown in soil inoculated with 

 the various organisms is very well shown by Plate IV. 



The figures in Table XIV show that all three of the organisms 

 caused a dwarfing of the barley, the two cultures of Helminthosporium 

 to a much greater extent than the Fusarium. The Minnesota strain 

 almost completely destroyed the plants. The effect of the three organ- 

 isms on the root systems is shown by Plate V. The nature of the injury 

 caused by severe infections of Helminthosporium is further illustrated 

 by Plate VI, where eight seedlings showing various degrees of infection 

 are shown beside a normal seedling of the same age grown in sterilized 

 soil. 



