Feb. 24. I9I9 Angular-Leafspot of Tobacco 227 



Fermentation tubes.— The tests were made in basal solutions of i per cent pep- 

 tone, to which was added i per cent of the following carbon compounds: Saccharose, 

 dextrose, lactose, maltose, glycerin, and mannit. Clouding occurred in the open 

 ends of all tubes in 48 hours, but the closed ends remained clear with a distinct line 

 across the inner part of the U. Tests with neutral litmus paper gave an acid reac- 

 tion with saccharose and dextrose, while the others were neutral or faintly alkaline. 

 No gas was formed with any of the compounds. 



The tests for acid production with dextrose and saccharose were repeated, with 

 loo-cc. portions of 2 per cent of each in 2 per cent peptone water. After 10 days the 

 reaction was determined with phenolphthalein as the indicator. Both solutions 

 showed acid production in excess of the controls as follows: Saccharose control, +6.6; 

 saccharose inoculated, +11. o; dextrose control, +8.8; dextrose inoculated, +12.6. 



Reduction op nitrates. — Nitrates are not reduced. 



Indol. — A moderate indol production was obtained in Dunham's solution. 



Uschinsky's solution. — Clouding w£i.s evident after 48 hoiurs and was only 

 moderate at seven days. The medium did not change color and no sciun or pellicle 

 was formed. 



Aerobism. — The organism appears to be strictly aerobic. 



Following the chart of the Society of American Bacteriologists, the 

 group number is 211.23220^ 33. 



SUMMARY 



A leafspot disease of tobacco which was prevalent in the flue-cured 

 belt in Virginia in 191 7 is described under the name "angular-leaf spot." 

 The disease has apparently been present to some extent for several 

 years and may have a wide distribution. 



The disease is caused by a specific organism, which is described as 

 "Bacterium angulatum." Rainfall is an important aid to infection, and 

 the development of the organism within the tobacco leaf is apparently 

 dependent to a marked degree on those predisposing factors which 

 promote a rapid, vigorous growth of the host. 



The disease produced losses in both yield and grade. These were 

 calculated in one field as a 20 per cent reduction in yield and a 40 per 

 cent reduction in grade. 



LITERATURE CITED 

 (i) Clinton, G. P. 



1915. CHLOROSIS OK PLANTS WITH SPECIAL REFERENCE TO CALICO OP TOBACCO. 



In Conn. Agr. Exp. Sta. Ann. Rpt. 1914, p. 357-424, pi. 25-32. 



(2) DELACROIX, Georges. 



1905. LA ROUILLE BLANCHE DU TAB AC ET LA NIELLE OU MALADIE DE LA MO- 



SAiQUE. In Compt. Rend. Acad. Sci. [Paris], t. 140, no. 10, p. 678-680. 



(3) 



1906. RECHERCHES SUR QUELQUES MALADIES DU TABAC EN FRANCE. In Ann. 



Inst. Nat. Agron., s. 2, t. 5, p. 141-232, 17 fig. 

 {4) Honing, J. A. 



I914. DE"zWARTEROESTE" DER DELI-TABAK. (black RUST OF DELI-TOBACCO.) 



Bui. Deli- Proef Stat, i, 16 p., 2 pi. Literatuur, p. 16. 

 1 A very slight fluorescence is imparted to the medium with agar stroke. 



