Fusarium Blight of the Soy Bean 29 
Yellow, Medium Yellow, and Virginia were planted in a field 
which produced a large percentage of wilt in cowpeas in 1914. 
Two rows of cowpeas were planted in the same plot. By Septem- 
ber 1, when all the plants had fully matured, a small percentage 
of wilted cowpeas had been noted ; but no blighted so}^ beans were 
found. 
Similar data were obtained from observations on cowpeas and 
soy beans grown in the experimental plot devoted to plant breed- 
ing. In this 4- a ere plot, three or four rows of soy beans were 
alternated with three or four rows of cowpeas thruout the field. 
Some wilt occurred in practically every row of cowpeas in the 
plot, but careful examinations during the season failed to reveal 
a single so}" bean blighted with Fusarium sp. among IT standard 
varieties and 50 other unnamed selections. 
DISCUSSION OF THE RESULTS OF INOCULATION EXPERIMENTS 
In inoculation experiments soy beans and cowpeas, from the 
time of germination until 4 or 5 days after their appearance above 
the surface of inoculated soil, were often killed b}^ an organism 
which invaded the cotyledons and the growing tips. This was 
especially true if nearly pure sand was used instead of soil. It 
was not definitely proved that Fusarium was the cause of this 
condition, however, and no record of these cases was made in the 
results given above. 
In the results recorded, the cowpeas after 4 to 6 weeks were 
generally invaded well up into the stem and the plants were often 
killed after a period in which they showed, except for sporo- 
dochia, the striking symptoms commonly known to appear in 
connection with this disease in the field. On the other hand, the 
affected soy beans have shown symptoms only on the roots. Some 
of these were found to have typical discoloration in the x^dem 
areas but the root systems were never invaded to the extent that 
the plants showed the effects above the ground. A lack of vigor 
was apparent in many soy beans but it was uncertain without 
an examination of the roots whether this was due to the action of 
the organism or to more or less unfavorable conditions for plant 
growth. 
That reciprocal inoculations were successful in a number of 
cases can be seen from the results of certain of the above experi- 
ments in which plants of both hosts became infected by both 
strains of Fusarium. Certain other attempts were made, how- 
ever, in which all soy beans remained free from disease. Contrary 
to this, the cowpeas in the same flats always showed at least 
several plants typically diseased, regardless of whether they 
