434 
Journal of Agricultural Research 
Vol. Vffl, No. ii. 
in the greenhouse, were each inoculated when from 3 to 6 inches high 
with spores from sporodochia and with mycelium by introducing the 
material into incisions in the stems an inch or two below the surface of 
the soil. All of the plants in one flat were inoculated with the soybean * 
strain of Fusarium and all of those in the other with the cowpea strain. 
Checks and all inoculated plants except two cowpeas inoculated with the 
soybean strain and one with the cowpea strain, remained healthy. The 
test was repeated, using a freshly isolated strain of both organisms; and, 
since all but one of the plants remained healthy, this method of inocula¬ 
tion was discarded. 
Experiment II (Series 1).—In this experiment the soil in two flats 
A and B, in the greenhouse was inoculated with pure cultures of Fusarium 
spp. on cowpea and soybean, respectively. These cultures were then 
incorporated in the upper 4 inches of soil. 
The organisms had been grown on pieces of moistened, sterilized cow¬ 
pea stems until numerous sporodochia had formed. On April 12, 1916, 
20 North Carolina Black cowpeas and 20 Mammoth Yellow soybeans 
were planted in each flat. A third flat, containing uninoculated soil, 
was planted as a check. 
By June 4 a cowpea plant in flat B was noted to be diseased. Others 
had been observed to be affected by June 15, when all the plants were 
removed and examined. The results are presented in Table III. 
Table HI.— Results of growing soybeans and cowpeas in artificially inoculated soil 
Flat. 
Organism. 
Host. 
Total 
number of 
plants. 
Diseased plants. 
Number. 
Percentage. 
A 
Fusarium sp. on cowpea. 
[Cowpeas... 
\Soybeans. . 
20 
6 
30 
20 
3 
*5 
B 
Fusarium sp. on soybean. 
f Cowpeas.. . 
tSoybeans, .i 
20 
10 
50 
20 
7 
35 
c 
None (control). 
/Cowpeas.. . 
/Soybeans.. 
20 
0 
0 
20 
0 
0 
Experiment II (Series 2.)-*— Since the percentage of diseased plants in 
series 1 is relatively small, the test was repeated, using another strain 
of each organism and Clay cowpeas instead of the North Carolina Black 
variety. Each plant in this test was injured by incision below the surface 
of the inoculated soil. The period of growth of these plants extended 
from July 29 to September 1, at which date the plants were fully matured, 
The results of this series are recorded in Table IV. 
Experiment II (Series 3).—The test in series 2 was duplicated be¬ 
tween September 7 and November 20, with no resultant increase in the 
percentage of infections. 
Experiment III.—Since it was thought that the strain of Fusarium 
on soybean had to a degree lost its virulence by growth in culture, soy- 
