212 
Journal of Agricultural Research 
Vol. XXVI, No. 5 
trend of these factors very closely, and it is felt that they can be used 
safely as a basis for comparison. 
Tabus VIII. —Amount of autumnal infection by Helminthosporium on the under - 
ground parts of Early May and Harvest Queen wheats sown on different dates in a 
naturally infested field at Granite City , IU. t in 1920 
Approxi¬ 
mate 
Approxi¬ 
mate 
Fall data. 
Spring data.® 
Variety. 
Sowing 
dates. 
mean 
tempera¬ 
ture 
during 
growing 
period in 
fall. 
total 
rainfall in 
inches 
during 
growing 
period in 
fall. 
Date of 
observation. 
Percent¬ 
age of 
tiller 
infection. 
Date of 
observation. 
Percent¬ 
age of 
tiller 
infection. 
Early May.... 
Sept. 
21 
°E. 
61. 9 
2. 84 
Nov. 12 
64. 7 
May 13 
91.05 
Do. 
Oct. 
4 
59-4 
2. 72 
...do. 
26.3 
88. 00 
Do. 
Oct. 
11 
57-6 
2. 72 
...do. 
18.5 
...do. 
74-24 
Harvest Queen. 
Sept. 
21 
61. 9 
2. 84 
...do. 
61. 7 
No data taken on 
Do. 
Oct. 
4 
59-4 
2. 72 
...do. 
45 - 1 
Harvest 
Queen 
Do. 
Oct. 
11 
57-6 
2. 72 
...do. 
10. 9 
on account of 
• 
complications 
from rosette 
disease. 
0 These data are based on determinations which were very kindly made by Dr. R. W. Webb of the Office 
of Cereal Investigations. 
Table IX. —Amount of autumnal infection by Helminthosporium sativum in Turkey 
and Harvest Queen wheats sown on different dates in a naturally infested field at Granite 
City , III., in 1921 
Variety. 
Date sown. 
Date re¬ 
moved. 
Ap¬ 
proxi¬ 
mate 
mean 
tem¬ 
pera¬ 
ture 
during 
fall 
growing 
period. 
Ap¬ 
proxi¬ 
mate 
mean 
rainfall 
during 
fall 
growing 
period. 
Age of 
plants 
in days 
from 
seed¬ 
ing. 
Per¬ 
centage 
of 
plants 
in¬ 
fected. 
Degree of infec¬ 
tion. 
Turkey. 
Sept. 
20 
Oct. 
17 
°F. 
63.6 
Inches. 
3 - 46 
27 
93. IO 
Abundant. 
Do. 
Oct. 
1 
Oct. 
26 
59-9 
. 70 
25 
l 8 . 20 
Slight. 
Do. 
Oct. 
12 
Nov. 
8 
57-8 
‘97 
27 
II. IO 
Very slight. 
Do. 
Oct. 
19 
Nov. 
17 
54-0 
I. 23 
29 
13.4O 
Do. 
Do. 
Oct. 
27 
Nov. 
21 
49. 8 
4. 91 
2 5 
19. 20 
Trace. 
Do. 
Nov. 
11 
Dec. 
12 
44-3 
4. 86 
31 
6. 74 
Do. 
Harvest Queen. 
Sept. 
20 
Oct. 
17 
63. 6 
3 - 46 
27 
64. 50 
Abundant. 
Do. ; . 
Oct. 
1 
Oct. 
26 
59-9 
. 70 
2 5 
19. 70 
Slight. 
Do.. 
Oct. 
12 
Nov. 
8 
57.8 
•97 
2 7 
5 - 30 
Very slight. 
Do. 
Oct. 
19 
Nov. 
17 
54 -o 
1. 23 
2 9 
11. 70 
Do. 
Do. 
Oct. 
27 
Nov. 
21 
49.8 
4. 9 1 
2 5 
14 - 5 ° 
Trace. 
Do. 
Nov. 
11 
Dec. 
12 
44-3 
4. 86 
31 
3.70 
Do. 
In all of the field experiments the amount of disease is expressed on the 
basis of the percentage of the number of plants infected on the under¬ 
ground parts, chiefly the sheaths, culms, and subcrown intemodes. No 
account of the severity 6f the infection of individual plants was taken in 
arriving at this percentage. 
