Mar. 3 , i 9a3 Further Studies of Corticium vagutn on Potato 
763 
shoots of the first two crops remained practically free from injury (PI. 
1, A, B). The growing tips of these secondary stems showed no indica¬ 
tion of injury, while such injury as did occur was very slight and con¬ 
fined entirely to the outer layers of the cortex. 
Table II .—Daily soil temperatures and precipitation for Madison , Wis., for the months 
of May and fune , igig 
Date. 
Soil temperature at depth of— 
2 inches. 
4 inches. 
Max. 
Min. 
Mean. 
Mean. 
°C. 
°C. 
°C. 
°C. 
May 1 
9.0 
6.0 
7-5 
6. 2 
2 
8.5 
3 
9-5 
• 7 
8.2 
7.0 
4 
14. 8 
7.0 
10. 9 
8.7 
5 
13.8 
7-5 
10. 6 
8-5 
6 
14.8 
7.0 
10. 9 
8.0 
7 
21. 2 
7-5 
14.4 
10.9 
8 
16. 2 
8.0 
11.1 
9.4 
9 
20.0 
5 -o 
12.5 
9.2 
10 
20.9 
6.0 
13-4 
9.8 
11 
1 23.6 
6-5 
16. 5 
11.1 
12 
22.9 
8.0 
15-4 
12.6 
13 
1 22.8 
6.8 
14-8 
13-9 
14 
22. s 
7-5 
15-0 
13-5 
15 
17.2 
7.8 
12.5 
10.3 
16 
19-5 
9.0 
14.2 
12. 0 
17 
22. 5 
7-5 
15-0 
14.9 
18 
24-5 
7.0 
15-7 
14-5 
19 
20. 0 
10. s 
15-2 
13-5 
20 
13-8 
7.0 
10. 4 
8.2 
21 
22 
23 
17-5 
10.5 
14. 0 
11. 8 
24 
23. 2 
6.5 
14.8 
12.6 
25 
27-8 
9-5 
18.6 
16.4 
26 
27.8 
11.4 
12.6 
10.4 
27 
3 °-o 
13-0 
2 i -5 
19-3 ! 
28 
30-5 
14. 2 
22.3 
20.1 { 
29 
32.5 
14. 0 
23.2 
21.0 i 
30 
32.8 
15.0 
23.9 
31.7! 
31 
32. 2 
18. 0 
25 -1 
22.9 i 
Soil temperature at depth of— 
Rain¬ 
fall. 1 
Date. 
2 inches. 
4 inches. 
Rain¬ 
fall. 1 
Max. 
Min. 
Mean. 
Mean. 
Inches. 
°C. 
°C. 
°C. 
°C. 
Inches. 
0. 21 
June 1 
28.5 
19.0 
23-7 
21.5 
0. 75 
. 0 
2 
2 7 - 5 
18. 5 
23.0 
20. 8 
_ -37 
•33 
3 
26. 0 
19.0 
22. 5 
20.3 
Trace. 
. 21 
4 
22. 0 
14.0 
18. 0 
15-8 
•39 
. 0 
5 
23. 0 
14.0 
18.5 
16.3 
. 01 
•63 
6 
24.1 
14.0 
19. 0 
16.8 
.04 
. 0 
7 
25 - 5 
13-0 
19. 2 
17.0 
.01 
. 0 
8 
28. 0 
ii -5 
20. 2 
18.0 
. 0 
. 0 
9 
28. 2 
20. 5 
24-3 
22.1 
. 18 
. 0 
IO 
29. 8 
18. 0 
23-9 
21. 7 
.18 
. 0 
11 
29 - 5 
17. 6 
23-5 
21.3 
• 74 
. 0 
12 
29. 0 
19. 0 
24. 0 
21.8 
. 0 
. 0 
13 
31-0 
20. 0 
25-5 
23-3 
. 02 
Trace. 
14 
30-5 
20. 5 
25-5 
23-3 
.6 
•03 
15 
21.8 
21. 0 
26. 4 
24. 2 
. 0 
.09 
16 
30. 0 
22. 0 
26. 0 
23.8 
Trace. 
.0 
17 
31-2 
22.0 
26. 6 
24.4 
. 0 
. 0 
18 
31-8 
21. 0 
26.4 
24. 2 
. 0 
. 0 
19 
34-5 
21. 6 
26.0 
23.8 
. 02 
Trace. 
20 
33-5 
22. 5 
28.3 
26.1 
Trace. 
. 2 
21 
32.5 
21.1 
26.8 
24.6 
Trace. 
. 01 
22 
29.1 
21. 0 
25.0 
22.8 
Trace. 
. 01 
23 
27. 0 
21. 8 
24.4 
22. 2 
Trace. 
. 0 
24 
28.8 
2 i -5 
25-1 
22.9 
_ -05 
. 0 
25 
31.8 
21. 0 
26. 0 
23.8 
Trace. 
.0 
26 
27-5 
21.8 
29.6 
27.4 
. 0 
! .0 
27 
23.8 
19*5 
21.6 
19.4 
. 0 
i .0 
28 
30-5 
15 - 2 
22. 8 
20. 6 
. 0 
i . 0 
29 
32.8 
16. 0 
24.4 
22. 2 
. 0 
| . 02 
i 1.72 
30 
3-4 
17-5 
25- 7 
25-7 
. 0 
1 The data on the daily rainfall here presented were obtained from the monthly meteorological summary 
for May and June, 1919, published by the local office of the U. S. Weather Bureau, Milwaukee,, Wis., 
v. 24, p. 36-37 and 44 - 45 - 
For the entire period from April 26 to May 25 an average daily mean 
temperature of 13.5 0 C. was maintained at a depth of 2 inches. For¬ 
tunately for the purpose of the experiment, between May 25 and 28 
the weather turned suddenly warmer and the soil temperature at once 
arose to an average daily mean of 23.5 0 (fig. 1). This high daily mean 
was maintained thereafter until the conclusion of the experiment. 
As is evident from the temperature data submitted in Table II, the 
stems grown from the tubers planted April 28 to May 7 grew through 
cold soil at temperatures ranging on the average well below 21 0 C.—the 
upper temperature limit shown in the greenhouse experiments at which* 
the fungus may attack and destroy the young growing tips. The low 
temperatures which were maintained up to May 24 so retarded the 
growth of the young shoots as to afford opportunity for the accumulation 
of the fungus in the sinus of the young buds, resulting finally in the 
serious destruction of the growing points noted in the two earlier crops. 
In view of the very low temperatures maintained during the early part 
of May it is interesting to recall that growing-point destruction was 
