AN INFLUENCE OF MOISTURE ON BEAN WILT' 
By Bewis T. IvEonard * 
Assistant Physiologist, Soil Bacteriology Investigations, Bureau of Plant Industry^ 
United States Department of Agriculture 
In 20 years’ experience with the inoculation of legumes there have 
arisen only two noticeable failures in field work which could not be 
attributed to soil or climatic conditions or to the lack of efficiency on 
the part of the culture involved. The first case occurred with cowpea, 
evidenced by normal growth in the plants from untreated seed and 
sickly plants from the inoculated cowpeas. The other failure occurred 
in conjunction with the inoculation of navy bean, Phaseolus vulgaris, 
on the farm of the Office of Forage Crop Investigations at Redfield, 
S. Dak., in 1920 and was brought to my attention by Messrs. R. A. 
Oakley and H. L. Westover of that office. In the latter case many 
of the plants from beans which had been treated with a pure liquid 
culture, such as is distributed by the Department of Agriculture, died 
during the growing season, and the damage was sufficiently extensive 
to be rather noticeable in comparison with the rows of plants from the 
seed planted in the dry condition. It was estimated that 90 per cent 
of the crop was killed among the treated beans, whereas the loss was 
very slight among the plants which were uninoculated. A duplicate 
experiment with two different cultures, made on different pieces of 
ground at Redfield in 1921, gave an average loss of 25 per cent, due 
to treatment with liquid culture. 
The possibility that the bean legume organism assumes a definite 
pathological r 61 e was considered, but this theory has been completely 
discarded since the publication of the work of Miss Florence Hedges,* 
who isolated and described an entirely different organism as the cause 
of this disease. The material used by Miss Hedges was obtained at 
Redfield, S. Dak. 
The elimination of the possibility first mentioned led to the con¬ 
sideration of a second theory regarding the prevalence of the disease— 
that is, that some constituent of the medium employed to grow the 
culture of legume bacteria exercises a stimulating influence on the 
pathogenic organisms already in or on the seed. Miss Hedges found 
that the causative organism of the disease in question was generally 
present in the seeds which were used in the experiment. 
EXPERIMENTAL PLAN 
Attempts made to reproduce this diseased condition by the appli¬ 
cation of water and solutions containing the constituents of the media 
to beans which were planted on the Arlington Experimental Farm, 
Rossyln, Va., gave practically no definite results in one year, despite 
1 Accepted for publication Sept. 2 , 1922. 
* A large amount of credit for the successful carrying out of this experiment is due to Mr. H. L. Westover 
and Mr. Samuel Carver of the Office of Forage Crop Investigations. 
> Hbdgks, Florence, a bacteriai, wilt of the bean c vtjsed by bacterium flaccumfaciens nov. sp. 
In Science, n. s., v. 55, p. 433-434* 1922. 
Journal of Agricultural Research, 
Washington, D. C. 
acj 
Vol. XXIV, No. 9 
June 2, 1923 
Key No. G-307 
(749) 
