Nov. 3, 1923 
Helminthosporium Disease of Wheat 
203 
Table III.-'-Effects of soil temperatures on the infection of Harvest Queen (•winter ) 
wheat seedlings with Helminthosporium sativum cultures No. 51a and 392, at Madison , 
Wis., in 1921 and 1922 
Experiment 1. 
Experiment 2. 
Experiment 3A. 
Experiment 3B. 
Artificially inoculated 
soil (culture 51a). 
Started Feb. 7, 1921; 
ended Feb. 23, Mar. 12 
and x8, 1921. Soil 
moisture 44.4 per cent 
of moisture-holding 
capacity. 
Artificially inoculated 
seed (culture 51a). 
Started Mar. 3, 1921; 
ended Mar. 21, 1921. 
Soil moisture 43.2 per 
cent of moisture-hold¬ 
ing capacity. 
Seed inoculated with a 
water suspension of 
culture 51a containing 
105,200 conidia per cc.; 
started Apr. 3, 1921; 
ended Apr. 27, 1921. 
Soil moisture 33.5 per 
cent of moisture¬ 
holding capacity. 
This experiment was 
carried on at the same 
time and in the same 
manner as experiment 
3A except that the 
seeds were inoculated 
in a water suspension 
containing 6,57s co¬ 
nidia per cc. 
Average 
soil tem¬ 
pera¬ 
tures. 
Num¬ 
ber of 
plants. 
Infec¬ 
tion 
rating. 
Average 
soil tem¬ 
pera¬ 
tures. 
Num¬ 
ber of 
plants. 
Infec¬ 
tion 
rating. 
Average 
soil tem¬ 
pera¬ 
tures. 
Num¬ 
ber of 
plants. 
Infec¬ 
tion 
rating. 
Average 
soil 
tem¬ 
pera¬ 
tures. 
Num¬ 
ber of 
plants. 
Infec¬ 
tion 
rating. 
°C. 
0 8 
94 
24. 7 
°C. 
16 
117 
5-5 
°C. 
12 
104 
7. 2 
°C. 
12 
8 
0. 6 
b 12 
84 
36.6 
20 
117 
31. 2 
16 
Il8 
12. 2 
16 
Il8 
IS- 2 
c 16 
103 
21. O 
24 
109 
75-2 
20 
Il8 
46.8 
20 
Il6 
22. 7 
c 20 
94 
3 1 * 5 
28 
112 
73 - 8 
24 
d 55 
43-0 
24 
ii 6 
41. 6 
c 24 
97 
31. 0 
32 
114 
69. O 
28 
“5 
70.7 
28 
118 
46. 0 
C28 
88 
48. 6 
34-5 
98 
41. I 
32 
IOI 
79.2 
32 
109 
48.6 
c 3 2 
e 35 
78 
70 
74-9 
54 - 7 
34-5 
<* 79 
67.9 
34 - S 
105 
33-9 
Experiment 4. 
Experiment 5. 
Experiment 6. 
Summary./ 
Artifically inoculated 
seed (culture 51a). 
Started Apr. 29, 1921; 
ended May 21, 1921. 
Soil moisture 32.8 per 
cent of moisture-hold¬ 
ing capacity. 
Consolidated tempera¬ 
ture data from com¬ 
bined soil tempera¬ 
ture and moisture se¬ 
ries. Moisture data 
given in Table VII. 
Artificially inoculat¬ 
ed seed (culture 392). 
Started May 4, 1922; 
ended May 26, 1922. 
Artificially inoculated 
soil (culture 392). 
Started May 20. 1922, 
ended June 2, 1922. 
Soil moisture 52.2 per 
cent of moisture-hold¬ 
ing capacity. 
Average amount of infection 
at each soil temperature 
in the six experiments 
with Harvest Queen (win¬ 
ter) wheat seedlings. 
Aver¬ 
age 
soil 
tem¬ 
pera¬ 
tures. 
Num¬ 
ber of 
plants. 
Infec¬ 
tion 
rating. 
Aver¬ 
age 
soil 
tem- 
I pera- 
i tures. 
Num¬ 
ber of 
plants. 
Infec¬ 
tion 
rating. 
Aver¬ 
age 
soil 
tem¬ 
pera¬ 
tures. 
Num¬ 
ber of 
plants. 
Infec¬ 
tion 
rating. 
Average 
•soil tem¬ 
peratures. 
Num¬ 
ber of 
plants. 
Infec¬ 
tion 
rating. 
°C. 
12 
16 
20 
24 
28 
32 
34- 5 
99 
99 
S <5 
32 
48 
24 
59 
O. O 
.8 
13. 2 
48. 5 
47-9 
26.3 
9.6 
°C. 
12 
16 
20 
24 
28 
32 
34-5 
167 
175 
170 
167 
167 
174 
156 
16.5 
19-5 
55-3 
71. 7 
81. 2 
54-S 
8.7 
°C. 
12 
16 
20 
24 
28 
32 
34- 5 
117 
121 
117 
117 
117 
IOI 
c 55 
6. 2 
14. 5 
17. 0 
29. 8 
53-6 
79-3 
64. 0 
°C. 
12 
l 6 
20 
24 
28 
32 
34- 5-35 
109 
121 
112 
99 
109 
100 
88 
5*3 
10. 8 
27-3 
47.0 
55-2 
59*i 
28.6 
a Ended Mar. 18. 
Ended Mar. 12. 
« Ended Feb. 23. 
d Stand reduced by mice. 
< Plants in one pot lost during experiment on account of leak in pot.. 
/ This summary does not include the 8° or 12 0 temperature data from experiment 1, since these are for 
older plants. 
