Mar. io, 1923 
Rosette Disease of Wheat and Its Control 
781 
Plainly the results from this series of experiments do not show any 
striking influence of these substances upon the development of the 
disease. 
In the fall of 1920 this work was modified, using smaller plots and 
adding fertilizer materials in somewhat greater quantities per acre. 
The plots in this experiment were 4 by 6 feet in size, consisting of uni¬ 
formly infested soil. Harvest Queen (white-chaffed Red Cross) seed 
from a field free from the rosette disease was sown in each plot on Octo¬ 
ber 11. The fertilizers and lime, except the acid phosphate, were applied 
just before seeding, the latter was applied just after seeding. 
Table IV gives the treatments, the rates of application, and the 
extent of disease which developed in the plots. 
As in the previous experiment, the results from this series show 
practically no influence upon the development of the disease. The 
slight variations in the extent of disease developing in the different plots 
during both seasons is easily within the limits of experimental error. 
In fact, such small differences are not apparent when the plots are 
observed casually. 
In order to determine any possible influence of cropping methods upon 
the disease, a plot of infested land was sown to various crops in the 
spring of 1919. Another portion of the infested land was summer 
fallowed and still another portion of it was left in winter wheat which 
was badly infested with rosette disease. Table V gives the arrangement 
of these plots and the crops used. In the fall of 1919, after plowing and 
fitting, these plots were sown crosswise with a 54-inch drill strip of 
Harvest Queen (Salzer’s Prize-taker) wheat. 
Table V. —Influence of previous crops and summer fallow upon the control of rosette 
disease on infested land during the spring of 1920, at Granite City , III. 
Crop grown in spring of 1919. 
Crop grown in fall and spring of 1919-20. 
Percentage of 
wheat plants 
showing dis¬ 
ease in 1920. 
Potatoes. 
Harvest Queen (Salzer’s Prize-taker) wheat. 
.do. 
98 
98 
94 
98 
97 
93 
Rape. 
Winter wheat (affected by- 
rosette). 
Summer fallow. 
.do. 
.do. 
Buckwheat. 
.do. 
Com. 
.do. 
In the spring the rosette disease developed with practically uniform 
severity on all the plots. Table V gives the relative percentage of the 
disease in each plot. While there was some variation in the percentage 
of disease occurring in these plots, the differences were very slight and 
the disease control was practically negative. 
In the fall of 1920 Harvest Queen (white-chaffed Red Cross) seed was 
sown on infested land, part of which had been in summer fallow for two 
years and other parts in diseased and in healthy winter wheat the pre¬ 
vious season.^ During the following spring the rosette disease developed 
in all the plots sown to the Harvest Queen (white-chaffed Red Cross) 
seed, and in no case was it possible to distinguish any difference in the 
percentage of disease present in the plots previously occupied by wheat 
and fallow. All contained from 90 to 95 per cent of diseased plants, 
showing conclusively that no control was obtained. 
