II. Further Studies on Bacterial Blight of Soybean* 
It will be recalled that two papers on bacterial blight have appeared during 
the past year, one from investigations conducted in Wisconsin by Miss Coerper 
(1) and the other in North Carolina by the junior writer (5). The disease in 
the case of the former of these accounts, is ascribed to a hitherto undescribed 
organism, Bacterium glycineum, and in the latter to an organism to which the 
name Bacterium sojae has been applied. Furthermore, the paper by Miss 
Coerper appeared in published form, while the junior writer’s manuscript 
was in press, so that opportunity was not afforded for a critical comparative 
study of the two diseases and of the causal organisms. The foot-note (l.c.p. 
120) accompanying this account was prepared by comparison with the pub¬ 
lished descriptive report, as has been indicated. Through the courtesy and 
kindness of Miss Coerper and of Dr. L. R. Jones, specimens and cultures have 
subsequently been received and it is, therefore, the present purpose to record 
the results of these comparative studies in order to clarify the problem of the 
identity of these soybean bacterial blight diseases. 
DIFFERENCE IN APPEARANCE OF DISEASES 
Comparison of type specimens of diseased leaves shows that no differences 
are present which are sufficiently distinctive to make it possible to separate 
the two in the field. As previously indicated, however, minor differences, as 
in the color of the diseased areas and of the dried bacterial exudate, are ap¬ 
parent, which no doubt vary dependent upon weather conditions and the stage 
of development of the disease. 
Even though the disease in North Carolina has been quite prevalent during 
the present season, it appears to be confined to the leaves and has not been 
observed also on stems and pods as is the case in Wisconsin. It is doubtful 
if any means of identification save isolation of the causal organism can be re- 
* 
lied upon. Isolations made during the present season from leaves collected in 
the vicinity of Raleigh, Oxford, and Edenton, N. C., agree with those of pre¬ 
vious seasons. Opportunity has not been afforded, therefore, to observe under 
field conditions, the two leafspot diseases, which as indicated by the cultural 
studies to follow, must occur in Wisconsin. 
ORIGIN OF CULTURES 
Five strains of soybean blight, four from Wisconsin and one from North 
Carolina, have been employed in the cultural studies. Data on those from 
Wisconsin can best be presented by quoting rather fully Miss Coerper’s notes 
of explanation which accompanied the cultures: 
No. 268. Isolated August 29, 1917. Naturally infected leaves were placed in 
damp chamber over night. Drops of bacterial exudate developed 
and streaks on potato agar slants were made by direct transfer. 
One of these isolations proved pathogenic when atomized on soy¬ 
bean leaves. Pathogenicity proved a number of times. Type 
strain. Brown’s peptone media. Employed in all cultural and 
inoculation work in soybean blight studies. 
*Reprinted from Phytopathology 11: No. 1, pp. 18-24, 1921. 
