BUNT, OR STICKING SMUT, OF WHEAT. 
9 
25-foot row. The yield was from 1,000 to 1,200 heads to the row. 
Only a count of heads was made. The results are shown in Table 6. 
Table 6. — Relation of soil temperature to bunt infection as shown by the percentages 
of bunted heads of wheat, Hybrid 143, sown at Pullman, Wash., on successive dates 
in 1913. 
[The mean soil temperature stated is for the period from sowing to the appearance of the first blade.] 
Date sown. 
Julv28. 
Aug. 11. 
Aug. 20. 
Sept. 1.. 
Sept. 1.. 
Sept. 10 
Sept. 15 
Mean 
soil i Bunted 
temper- heads, 
ature. 
C. 
^5.0 
18.9 
25.4 
18.3 
18.3 
19.7 
15.6 
Per cent. 
' 0. OS 
.60 
.32 
.19 
.23 
2.30 
3.00 
Date sown. 
Sept. 22 
Sept. 30 
Oct. 13. 
Oct. 17. 
Oct. 25. 
Nov. 7.. 
Nov. 11. 
Mean 
soil , Bunted 
tern er- heads, 
ature. 
i 
a. 
Per cent. 
10.0 
50.00 
10.0 
86.00 
8.1 
92. 90 
8.1 
97.30 
5.5 
91.00 
4.2 
48.20 
3.0 
55.30 
For the sowings in the spring of 1914 a soil thermograph *was not 
available. The preparation of the seed was the same as in the pre- 
ceding experiment. When each sowing was made in the field a pot 
was filled with the same soil and sown with the same seed, later to 
be taken to the greenhouse and placed under a bell jar where mois- 
ture conditions could be made to approximate those in the field. As 
soon as the seedlings had emerged from the coleoptile they were 
transplanted to the field immediately alongside the field row. These 
two contemporaneous sowings headed about the same time; that is, 
the time gained by the quicker germination in the greenhouse was 
lost by the transplanting. The comparatively hi^h bunt infection 
in the sowing of March 1 9 in the greenhouse was evidently because of 
the relatively low temperature, a condition resulting from absence of. 
artificial heat and deficient sunshine. The results are shown in 
Table 7. 
Table 7. — Relation of soil temperature to bunt infection as shown by the percentage 
of bunted plants of wheat, Hybrid 143, sown at Pullman, Wash., on successive 
dates during the period from March 3 to April 1, 1914- 
Date of sowing. 
Outdoor plants. 
Greenhouse plants. 
Number. 
Infection. 
Number. ' Infection. 
Mar. 3 
101 
99 
130 
100 
78 
Per cent. 
76.2 
60.6 
56.2 ; 
35.0 
29.5 ' 
1 Per cent. 
37 5.4 
Mar. 7 
32 6. 2 
Mar. 19 
15 j 46.7 
Mar. 28 
27 3.7 
Apr. 1 
| 
Fall sowings of bunt-inoculated seed of Hybrid 143 were begun 
on August 14. These early sowings were badly damaged by grass- 
hoppers, a fact which possibly may be related to the high per- 
centage of bunt in the first three sowings. This series of sowings 
was continued in the spring of 1915, using the same wheat, until the 
78298—24—2 
