866 
Journal of Agricultural Research 
Vol. XXIII. No. ii 
RELATION OF DATE OF PLANTING TO THE DEVELOPMENT OF SEEDLING- 
BLIGHT IN CORN 
The general field observations during the past two seasons have 
demonstrated beyond question the influence of soil temperature upon the 
seedling-blight of corn and, in themselves, have corroborated the soil- 
temperature studies in tanks in the greenhouse. A preliminary series 
of periodic planting experiments with corn was started in the spring of 
1921 to check more exactly the soil-temperature tank results. The 
first planting, April 20, germinated when the mean soil temperature was 
about 12 0 C.; the second planting, April 30, germinated a few days before 
most of the corn was planted in the vicinity of Madison. While the 
average mean soil temperature in this period was about the same as 
during the previous period, the daily mean temperature, as shown 
graphically in figures 2 and 14, did not run as low at any single period 
as in the previous germination period. The last planting, May 31, 
germinated in a soil at about 20°. The percentage stand of plants for 
the three periods and temperatures are given in Tables XV and XVI 
and shown graphically in figures 2 and 14. 
Table XV .—Average soil and air temperatures during the germination periods for corn 
at Madison , Wis., IQ21 
Duration of germination period. 
Average soil tempera¬ 
tures, 4 inches deep. 
Average air tempera¬ 
tures, 6 inches above soil. 
Dates. 
Num¬ 
ber of 
days. 
Mean. 
Min. 
Max. 
Mean. 
1 
Min. ! Max. 
i 
1 
Apr. 20 to May 10. 
Apr. 30 to May 16. . 
May 21 to 27. 
20 
16 
6 
°C. 
II. 7 
II. 7 
18.8 
# C. 
8. 1 
8.0 
15-5 
°C. 
15-2 
15*5 
26.8 
# C. 
10. 8 
9*7 
20. 1 
°C. ! °C. 
6. 3 1 I 5 * 5 
4 * 8 ; 14. 4 
IS- 7 25. 2 
Table XVI. — Relation of date of planting to development of seedling-blight of corn at 
Madison , Wis., in 1 Q 2 I 
Date of planting. 
Average 
number 
of days for 
emergence. 
Average percentage of 
stand. 
Disease- 
free seed. 
Disease- 
free seed 
inoculated 
with 
Gibberella 
saubmetii. 
Apr. 20. 
20 
16 
6 
90 
91 
94 
20 
78 
93 
Aor. 30 .... 
May 21 .. 
The first planting was most severely affected by blight, 70 per cent of 
the plants being killed during the seedling stage. Most of these were 
blighted during germination or just before emergence. The mean 
daily soil temperature, as shown graphically in figure 2, contributed 
directly to this blighting. The soil temperature following sowing was 
