PLATE I 



Helminthosporium sativum P. K. B. grown on potato dextrose agar at 

 the following temperatures : 



(i) o 2C, (2) 6 8C, (3) 13 i5C, 

 (4) 17 22C, (5) 2i 2 4 C., (6) 30 32C., 

 (7) 34-35C., (8) 40 42C. 

 Incubated 9 drys. 



PLATE II 



Helminthospcrium sativum P. K. B. grown on potato dextrose agar 

 at the following temperatures: 



(i) 3 - 6C, (2) I2-I 3 C, (3) I5-I8C, 

 (4) 20 2 3 C., (5) 27 28 C, (6) 31 33C. 



Incubated 7 days. 



PLATE III 



Marquis wheat showing the effect of Helminthosporium root-rot in 

 the following types of soil : 



A i. Heavy loam, soil inoculated with H. sativum P.K.B. 



A iC. Heavy loam, uninoculated, sterilized soil 



A 2. Sandy loam, soil inoculated with H. sativum P.K.B. 



A 2C. Sandy loam, uninoculated, sterilized soil 



A 3. Sand, soil inoculated with H. sativum P.K.B. 



A3C. Sand, uninoculated, sterilized soil. 



A 4. Peat, soil inoculated with H. sativum P.K.B. 



A 4C. Peat, uninoculated, sterilized soil. 



PLATE IV 



Lion barley plants, 3 weeks old, growing in soil inoculated with the 

 following organisms: 



1. Helminthosporium sativum P.K.B. Culture 82a, isolated from stunted 



barley plants in Minnesota 



2. Helminthosporium isolated from stunted wheat plants in Illinois 



3. Fusarium culmorum (W. Sm.) Saccardo 



4. Uninoculated, sterilized soil 



PLATE V 



Lion barley plants, 3 weeks old, showing effect of the following soil 

 organisms on development of root systems 



1. Helminthosporium sativum P.K.B. Culture 82a 



2. Helminthosporium from stunted wheat plants in Illinois 



3. Fusarium culmorum (W. Sm.) Saccardo 



4. Normal roots grown in uninoculated, sterilized soil 



PLATE VI 



Lion barley plants, 3^2 weeks old, showing effect of root infection by 

 Helminthosporium sativum P.K.B. The eight seedlings on the left were 

 grown in inoculated soil, the one on the right in uninoculated, sterilized soil. 



