Mar. 17,19*3 Influence of Soil Temperature on Seedling-Blight 
855 
INFLUENCE OF SOIL TEMPERATURE ON THE DEVELOPMENT OF SEEDLING- 
BLIGHT IN CORN 
The experiments on the relation of soil temperature to the seedling- 
blight of wheat have shown that blight does not occur much below I2°C., 
and that at 12 0 and above the wheat seedling becomes susceptible to 
attack. The investigations seem 
to demonstrate further that the 
response of the host to soil 
temperature rather than that of 
the parasite must be considered 
as the chief explanation of these 
differences. Accordingly, another 
series of experiments was started 
with a different host, namely, 
corn, which is a comparatively 
warm-climate crop and is sus¬ 
ceptible to the same parasite, 
Gibberella saubinetii. 
The seed for each series of ex¬ 
periments was taken from the 
same ear of corn. The method 
of inoculation and planting was 
identical with that previously de¬ 
scribed for wheat. Observations 
comparable to those recorded for 
wheat were made; in fact, in all 
but two series wheat was grown simultaneously with corn in the same tem¬ 
perature tanks. The data given in Table VII and shown graphically in 
figure 7 represent the average of seven different series of corn experiments. 
Fig. 7 . —Graph showing relation of soil temperature to 
the development of seedling-blight of corn. The dis¬ 
tance between the heavy and light lines shows the 
percentage of seedling-blight. Compare with seedling- 
blight of wheat in figures 5 and 6. 
Table VII .—Influence of soil temperature on the development of seedling-blight of corn 
{Average of seven experiments.] 
Average 
soil 
temper¬ 
ature 
°c. 
Average 
number of 
days to 
emerge. 
Control. 
Inoculated with Gibberella saubinetii 
Average of 
percentage 
germina¬ 
tion. 
Average 
percentage 
of healthy 
plants. 
Average 
percentage 
of germi¬ 
nation. 
Average 
percentage 
of healthy 
plants. 
Average 
percentage 
of blighted 
or diseased 
plants. 
8 
50 
O 
O 
O 
12 
I 5 * 7 
77 
72 
20 
II 
9 
l6 
9-7 
96 
92 
54 
12 
42 
20 
5-7 
97 
95 
89 
42 
47 
24 
5 -° 
92 
92 
100 
73 
27 
28 
3-6 
100 
100 
94 
93 
1 
32 
3-0 
97 
90 
100 
100 
36 
3-6 
98 
85 
97 
77 
a 20 
a No blighting; killed chiefly by high soil temperatures. 
The rate of development, at least during the seedling stage, was 
checked slightly by the introduction of the parasite at soil temperatures 
below 24 0 C., but above this no differences were detected. 
