Mar. io, 1923 
Rosette Disease of Wheat and Its Control 
777 
Stevens {33, p. 259) recognized the development of extra tillers or 
“shoots” as a characteristic of the rosette disease (called footrot by him), 
but apparently he did not regard this as a primary characteristic. He 
considered the browning and rotting of the basal portions of the plants as 
the most “constant” character of the disease. 
It is quite true that when the rosette disease is not observed until a con¬ 
siderable length of time after its first appearance in the spring, the dark¬ 
ening and rotting of the basal tissue might be considered, under certain 
conditions, as constant characters, but even these characters do not seem 
to hold in all localities where the disease occurs. 
When the rosette disease, as it occurs in different localities, is taken 
into consideration, the most constant or characteristic symptoms which 
have been found in three years of close observation, consist of (1) the 
arrested spring developments, (2) the excessive tillering, producing a 
rosette appearance, and (3) the dark blue-green color of the foliage in 
combination with the characters mentioned above. 
On the basis of our present knowledge, the presence of Helminthospo- 
rium lesions on, or a rotting of, the basal parts of wheat plants can not 
by themselves be considered diagnostic characteristics of the rosette 
disease. This Helminthosporium is found to cause considerable injury 
on many wheat varieties growing in the regions where the rosette disease 
occurs and which are not known to show the characteristic symptoms 
of rosette. Furthermore, this organism has been found attacking wheat 
in sections of the United States where the rosette disease is unknown. 
It is not the purpose of this paper to deal with the take-all and footrot 
type of diseases occurring in the United States, but it does seem advisable 
to give the principal characteristics of these troubles as found in this 
country, in order that they may be distinguished from the rosette disease. 
The field spotting caused by take-all and footrot is practically the same 
as that caused by the rosette disease. Field spots, however, tend to 
show up earlier in the spring in the rosette disease than in take-all and 
footrot. The first indication of the latter seems to be a yellowing of the 
affected plants, a condition not found in the rosette disease. Such 
yellow plants rapidly bleach out or develop a bronze color and die, after 
which they tend to remain erect in a rather stiff, upright position, or they 
may break over at the base due to a dry crownrot. When death is 
caused by the rosette disease, the plants turn brown without passing 
through the yellowing stage, and such plants droop to the ground and 
form a flat tuft of brown, dead leaves. 
A black plate or scalelike mat of mycelium is commonly found at the 
base of the tillers of plants affected by the take-all and footrot type of 
maladies, but this condition has never been found associated with the 
rosette disease. Premature ripening or the development of “white 
heads ” occurs in the former, but this does not occur in the rosette disease. 
Rather the opposite condition takes place—that is, delayed ripening of 
the partially recovered diseased plants. 
In general it may be said that the rosette disease of wheat may be 
diagnosed with certainty in the spring before healthy plants reach the 
boot stage. After this period the disease may, under certain conditions, 
be indistinguishable from certain insect and other troubles. The com¬ 
parative symptomatology of some of the insect maladies and the rosette 
disease will be taken up in a later paper prepared jointly between the 
