786 
Journal of Agricultural Research 
Vol. XXIII, No. 10 
those referred to above in connection with the writer's inoculations with 
Helminthosporium. It is entirely possible that Dr. Stevens restricts the 
name footrot to these limited types of plant injury, but if so the fact 
does not seem to have been made clear in his papers. Further, both in 
personal conferences and in public meetings subsequent to the publica¬ 
tion of his second paper (34), Dr. Stevens has stated that he has obtained 
from inoculations with Helminthosporium only the seedling and leaf 
lesions and that he has not obtained from pure-culture inoculations the 
dwarfing and excessive tillering, the diagnostic characteristics of the 
rosette disease. 
While experiments on pathogenicity conducted with the various 
organisms isolated from plants affected by the rosette disease have thus 
far failed to reproduce the characteristic symptoms of the disease, the 
writer does not feel justified in assuming that none of the organisms 
tested are the direct cause. As pointed out earlier in this paper, exper¬ 
ience with the winter-wheat plant shows that the peculiar symptoms 
manifested by this disease do not develop readily under greenhouse 
Fig. 2.—Graph showing tendency toward a correlation between the 
extent of rosette disease and the extent of Helminthosporium infec¬ 
tion on wheat plants not showing the rosette disease in six experi¬ 
mental plots at Granite City, Ill. 
conditions, and consequently further pathogenicity experiments are 
necessary before definite conclusions can be drawn. 
A tendency toward a correlation between the percentage of Helmin¬ 
thosporium and of the rosette disease is shown in figure 2. The curves in 
this graph represent the percentage of both manifestations upon wheat 
plants growing in six date-oi-seeding plots, the infestation of rosette 
disease in the soil being greatest in series A and rather gradually decreasing 
toward series F. The percentage of Helminthosporium injury in the 
various series was based on plants which escaped the rosette disease, thus 
enabling a direct comparison of results. On the whole the correlation 
between the two manifestations is rather striking and suggests a possible 
connection between Helminthosporium and rosette disease. 
In following the development of Helminthosporium infection on wheat 
growing in the plots near Granite City, Ill., and elsewhere, it is found that 
infection takes place in the fall. Usually this infection obtains in the 
15 Exhibited at the Chicago meetings of the American Phytopathological Society in December, 1920. 
