44 TECHNICAL BULLETIN 17 



The results obtained with Marquis wheat are not so clear, as all the 

 pots were molested more or less. The amount of injury caused by foot- 

 arid root-rot was very much less than on the barley. The Illinois strain 

 of Helminthosporium seemed to cause slightly more injury than the 

 Minnesota strain. 



This series was started in the greenhouse during warm weather early 

 in October when the temperature in the house was very high. The sub- 

 sequent development of the disease was most interesting. After three 

 weeks, the plants were thinned so that only three remained in each pot 

 except for those inoculated with H. sativum, culture 82a, of which only 

 three plants in each pot survived. These were badly stunted and in- 

 fected at the time. The pots were kept next to the outer west wall of 

 the greenhouse, where the temperature was always low during winter. 

 The position of the pots was changed periodically so that all the plants 

 would have more or less equal advantages as to sunlight. The plants 

 grew remarkably well, and after a few weeks scarcely any differences 

 could be detected between the different series. The barley stooled ex- 

 cessively and did not head well. The wheat was very good. At heading 

 time, late in April, there was practically no difference between either 

 the wheat or the barley plants grown in the clean soil and in the soil 

 inoculated with the Minnesota strain of H. sativum or the Fusarium 

 culmorum. The wheat in the soil inoculated with the Illinois strain of 

 Helminthosporium was very bushy and developed only one or two heads 

 per pot, while the other wheats developed from four to eight. The 

 Lion barley was also slightly poorer in the soil inoculated with the 

 Illinois strain than in the others. The barley did not head well, how- 

 ever, in any case. 



Under the conditions of this experiment, then, the Helminthosporium 

 caused more injury to Marquis wheat and Lion barley than the Fusa- 

 rium, both in the seeding and the mature stages. While the Minnesota 

 strain of Helminthosporium caused decidedly more seedling blight on 

 the barley, the Illinois strain caused slightly more stunting of the mature 

 plants. The Illinois strain caused more injury to the wheat at both 

 stages. 



SUMMARY AND CONCLUSIONS 



In recent years a foot- and root-rot of wheat, rye, and barley has 

 been serious in certain localities in Minnesota. A Helminthosporium 

 of the sativum type has been constantly isolated from the diseased 

 plants. In addition to causing a foot- and root-rot, the same type of 

 organism attacks the leaves and stems and especially the nodes, glumes, 

 and kernels of cereals and a large number of wild grasses. A strain 

 of the organism was isolated from a foot-rot of barley. A pure culture 

 was secured by isolating a single spore. The morphology of the organ- 



