424 
Journal of Agricultural Research 
Vol. VIII, No. ii 
philum has been reported as being productive of losses to cowpeas rang¬ 
ing from 2 to ioo per cent in Indiana, Missouri, Mississippi, Louisiana, 
Texas, Oklahoma, Georgia, Florida, North Carolina, South Carolina, and 
Virginia. 
APPEARANCE OF THE BLIGHT IN THE FIELD 
In 1916, soybeans were planted during the last two weeks in May. 
This is somewhat later than usual, being due to the late season and a 
period of drought. When the plants were 4 weeks old, they had attained 
a height of 2 to 3 dm, and were apparently still free from disease. The 
disease was first observed on July 25, when the affected plants were 
about 8 weeks old. Symptoms of the trouble could probably have been 
found a week or two earlier. Affected plants, all of the same age but 
varying in height from 2 dm. to 1 meter, were observed on the 25th. The 
fungus is believed to have stunted these small plants. In no case has the 
disease been observed on seedlings. 
The contrast in appearance of five healthy and five diseased plants is 
shown in Plate 95, E. The same type of clay soil was used in both 
pots, and the plants in each were grown out of doors under the same con¬ 
ditions. The plants shown in figure E were naturally infected from the 
soil. A considerable number of the leaves have fallen from the diseased 
plants, a portion of the petioles persist, the plants are dwarfed, and there 
is no evidence of wilting in any part of the plants. The foliage which 
persists on these plants is yellow as contrasted with the normal leaf green 
of healthy plants. 
The occasional absence of a definite wilting of the leaves has been 
noted in other wilt diseases. Orton (16, p. 10), in speaking of the 
cowpea disease caused by F. tracheiphilum, says: 
The term "wilt” is somewhat misleading, as the leaves usually drop off before 
there is any conspicuous wilting. The name was applied because of its relationship 
to the wilt of Cotton and watermelons, where this symptom is very prominent, and it 
seemed desirable to retain it for the cowpea disease. 
In the case cf the soybean disease, wilting is a less prominent symptom 
than in cowpeas, and is very seldom present at any stage of the disease. 
The plants, as a rule, drop all of their leaves and die without any evi¬ 
dence of wilting. Wilting has been observed in a very few instances 
in the field in the case of young plants. The woody nature of the stem 
and petioles probably accounts for the general absence of wilting in 
them, and the presence of well-developed mechanical tissues in the 
leaflets may account for their failure to manifest wilt. The possibility 
exists, also, that the physiological interaction of parasite and host 
differs from that exhibited by wilted cotton and watermelons infected 
with Fusarium spp. 
Instead of applying the name “wilt,” therefore, to the soybean 
trouble, it is perhaps desirable to call it “blight or wilt,” the former 
