May IS, 1920 



Halo-Blight of Oats 



169 



result of his inoculations as indicated on his colored plates is quite con- 

 tradictory. 



The chief differences between the two white organisms Pseudomonas 

 avenae Manns and Bacterium corona faciens , n. sp., are summarized 

 below : 



PSEUDOMONAS AVENAE MANNS. 



1. Produces typical blight lesions only 



when used with Bacillus avenae 

 Manns (a yellow organism). 



2. Spreads throughout the lesion when 



used alone. 



3. Virulence and \'iability on artificial 



media dependent upon association 

 with Bacillus avenae Manns. 



4. Viability and virulence greatly re- 



duced by a number of transfers. 



5. Growth feeble on artificial media. 



{Se^ 3, PI. VIII Jig. 3.) 



6. Liquefaction of gelatin stabs begins in 



7 to 12 days. 



7. Pitting of gelatin colonies begins in 7 



days. 



8. Visible growth in broth in 3 days. 



9. Manns does not record browning of 



broth or other media. 



10. Milk not coagulated in 30 days. 



11. Acid to litmus milk. 



12. No reduction of litmus milk recorded. 



13. Strictly aerobic. 



14. No ammonia produced. 



15. Nitrates reduced. 



16. Limits of growth, —5 to +15. 



17. Thermal death point 60° C. 



18. Internal structure of agar colonies 



amorphous. 



19. In hanging drop there are few motile 



organisms. 



20. Growth viscid on agar. 



21. Produces Clostridium forms in one 



week on nutrient glucose agar. 



22. Produces endospores. 



23. Does not form long chains. 



24. Shorter and thicker than Bacterium 



coronafaciens. Average size o. 7 5 by 



25. Lives over in the soil. 



26. Pathogenic on oats, com, timothy, 



barley, wheat, and bluegrass. 

 Group number 111.2223032. 



BACTBIUtTM CORONAFAaENS, N. SP. 



1. Produces tjrpical halo-blight lesions 



when used in pure culture. 



2. Found only about the point of infec- 



tion and not throughout the halo. 



3. Virulence and viability not dependent 



on another organism. 



4. Viability and virulence not reduced 



by transfer. 



5. Growth abimdant on artificial media. 



(See PI. 30, A, B, a, b.) 



6. Liquefaction begins in 3 days. 



7. Pitting begins in 3 days. 



8. Visible growth in i day. 



9. Broth and other media turned brown. 



10. Milk usually coagulated in 5 to 7 days. 



11. Alkaline to litmus milk. 



12. Litmus milk reduced. 



13. Facultative anaerobic. 



14. Ammonia produced. 



15. Nitrates not reduced. 



16. Limits of growth, —18 to -f-27. 



17. Thermal death point 47° to 48° C. 



18. Internal structure of agar colonies not 



amorphous. (See PI. 31.) 



19. Active motile organisms in hanging 



drop. 



20. Growth butyrous. 



2 1 . No clostridixim forms observed in any 



medium. 



22. Does not produce endospores. 



23. Forms chains and long filaments. 



24. Average size 0.65 by 2.3 /i. 



25. Lives over winter on the seed. 



26. Pathogenic on oats, barley, wheat, 

 and rye. 



Group number 221.2323023 



A bacterial disease producing lesions similar to those of the halo-blight 

 of oats has been described from tobacco (10). The lesions are similar to 



