Nov. 3, 1923 
Helminthosporium Disease of Wheat 
213 
In 1920 the autumnal data on all the plantings were taken on November 
12. Percentages were based on all the plants growing in 5 linear feet of 
drill row in each plot. These 5 linear feet consisted of five i-foot sections, 
four of which were taken 1 foot from the ends of the two drill rows adja¬ 
cent to the outside drill rows, and the fifth from the center row of each 
plot. 
Reference to Table VIII will show that early seeding tends to increase 
the amount of Helminthosporium infection on the underground parts of 
wheat plants. These results are in line with those obtained in the con¬ 
trolled soil temperature and soil moisture experiments, as the earlier field 
sowings were submitted to higher temperatures and moistures than the 
later sowings. 
It is of interest to note the results obtained the following spring on 
these same sowings of Early May wheat. On May 13 counts were made in 
the same manner as in the 
autumn, and while the per¬ 
centages of infection had in¬ 
creased considerably over 
those recorded in November 
it is noted that the general 
relationship between the sow¬ 
ings was the same as in the 
fall—that is, the early sow¬ 
ings still showed the greatest 
amounts of infection. This 
indicates that the influence 
of the date of fall sowing on 
the disease may extend con¬ 
siderably into the spring 
growing season. These data 
also indicate that the 
amounts of infection in the 
late sowings tend to catch 
up with those in the early 
sowings as the season ad¬ 
vances. 
Spring data on the Helminthosporium disease were not taken on the 
Harvest Queen plots, owing to complications from the rosette disease, 
which attacks this variety but does not affect Early May wheat. 
Undoubtedly the time factor played a considerable part in the results 
of this experiment, but it seems rather doubtful if this wholly accounts 
for the differences in the amount of disease in the different sowings. In 
order to eliminate the time element as far as possible from the field experi¬ 
ments, another method for taking data was adopted in the 1921 field 
experiments. Instead of making the disease determinations for all the 
plots at the same time, they were made as nearly as possible at a given 
time after the date of sowing of each plot. Three linear yards of plants 
were collected from each plot, 1 yard from near each end and 1 yard from 
the center of the middle drill rows. 
All data obtained in this experiment are shown in Table IX. 
From these results and the curves shown in figure 6 it is evident that 
the amount of disease tends to be greater when high temperatures and 
relatively high moistures prevail. 
Fig. 6. —Graph showing the influence of date of seeding in 
autumn on Helminthosporium infection of the subterra¬ 
nean parts of Harvest Queen and Turkey wheat plants 
grown in the field. Tabular data are given in Table IX. 
