Mar. xo, 1933 
Rosette Disease of Wheat and Its Control 
785 
best train connections and sent by special mail delivery. Ordinarily 
such material was in transit about 36 hours. The results of these plat¬ 
ings have shown no organism to be consistently associated with the vital 
crown tissues of plants in the early stages of the development of the dis¬ 
ease. By April 15 the same Helininthosporium which was found during 
the previous season made its appearance in the vital tissues of diseased 
plants and also on the tiller bases and the leaves of plants free from 
rosette disease. From this time on through the season this organism was 
found to be rather consistently associated with the disease. This was 
the period corresponding to the time when the work was started the 
previous year. 
During the spring of 1921 a large number of platings were made from 
plants in all stages of the disease.* Material was obtained from the 
experimental plots located near Granite City, Ill., and from the Indiana 
Agricultural Experiment Station plots located near Valparaiso, Ind. The 
plating was done by Dr. R. W. Webb in the laboratory of the Missouri 
Botanical Garden, at St. Louis, Mo., and by the writer in the laboratory 
of Plant Pathology at the University of Wisconsin. The results of these 
platings, which involved various media, reactions, and growing temper¬ 
atures, were the same for the Granite City material as those obtained the 
previous year. In general, it may be stated that Helminthosporium was 
much less consistently associated with the diseased plants collected in 
Indiana than with plants collected near Granite City, Ill. The results of 
early platings were the same for material from both sources. 
Experiments on the pathogenicity of pure cultures have been carried 
on with the predominating organisms isolated from diseased wheat 
plants. Of these organisms the Helminthosporium has been given the 
greatest attention. The results of this work show that this Helmin* 
thosporium is pathogenic on wheat, causing injuries which are apparently 
identical with those which heretofore have been produced by Johnson (1 3) 
with a similar or identical Helminthosporium isolated from wheat plants. 
The types of injury produced by the Helminthosporium isolated from 
wheat plants in the late stages of rosette disease may be summarized as 
follows: 
(1) Mild to severe infection of the coleoptile and first leaf of the ger¬ 
minating seed, often causing death of the seedling before emergence. 
(2) Mild to severe root injury. 
(3) Mild to severe infections of the underground leaf sheaths and 
tillers, from the seedling stage through the preboot and heading stage. 
(4) Infection of leaves, causing characteristic lesions which may occur 
anywhere at the ligule or on the blade. 
(5) Infection of leaf sheaths above ground, causing lesions very similar 
to those produced upon leaves; also infection of the nodes and intemodes. 
The same types of injury have been produced by the same type of 
Helminthosporium isolated from Wisconsin wheat not showing the symp¬ 
toms of the rosette disease of "wheat. Similar results also have been 
obtained by Stakman (32) with a Minnesota strain of Helminthosporium 
which appears to be very similar, if not identical, with the strains used 
by the writer. 
While Stevens (34) claims to have proved that the rosette disease 
(called footrot by him) (33) is caused by Helminthosporium, it is not clear 
that his evidence warrants this conclusion. Careful examination made 
by the writer of Dr. Stevens’ diseased plants from inoculation experi¬ 
ments 15 revealed only seedling and young-plant injuries identical with 
