834 
Journal of Agricultural Research 
Vol. XXXI, No. 9 
Table VI .—Effects of variations in soil and air temperature on the infection of 
young Goldcoin wheat plants with Ophiobolus graminis 
[The plants were grown in large chambers in which both temperature and humidity were controlled with¬ 
in relatively close limits. The soil was inoculated with the New York strain of the parasite, and 15 
disinfected seeds were planted in each of six containers for each temperature chamber. Experiment 
started March 31, 1923, and ended April 27, 1923] 
Temperature range, ° C. 
Number 
of plants 
Tiller- 
base 
infection 
rating 
Root- 
infection 
rating 
9.5 to 13.2___ 
70 
76 3 
97 9 
15.8 to 17.0_ 
68 
85 1 
96 4 
26.5 to 27.5____ 
59 
2L4 
36! 1 
Table VII .—Summary of data given in Tables III , IV, and V, arranged to show 
the influence of soil moisture on the infection of young Goldcoin wheat plants 
with Ophiobolus graminis 
Leaf blight 
Tiller-base infection 
Root infection 
Aver- 
Aver- 
Aver- 
age 
Low 
Medi- 
High 
age 
Low 
Medi- 
High 
age 
Low 
Medi- 
High 
soil 
soil 
urn soil 
soil 
soil 
soil 
um soil 
soil 
soil 
soil 
um soil 
soil 
temper- 
mois- 
mois- 
mois- 
temper- 
mois- * 
mois- 
mois- 
temper- 
mois- 
mois- 
mois- 
ature, 
ture 
ture 
ture 
ature, 
ture 
ture 
ture 
ature, 
ture 
ture 
ture 
°C. 
° C. 
° C. 
8 
0.9 
0.0 
0.0 
8 
20.3 
32.6 
24.9 
8 
56.9 
35.8 
55.5 
12 
22.9 
23.9 
32.3 
12 
66.8 
76.0 
65.3 
12 
71.0 
71.0 
78.9 
16 
23.0 
40.0 
61.2 
16 
75.4 
70.1 
86.6 
16 
73.1 
62.2 
91.6 
20 
10.9 
39.7 
48.4 
20 
51.1 
63.5 
80.5 
20 
59.4 
61.4 
83.7 
24 
4.2 
29.5 
47.8 
24 
27.3 
57.3 
67.1 
24 
38.4 
53.1 
78.9 
28 
1.6 
.7 
16.0 
28 
5.5 
30.7 
46.7 
28 
5.5 
34.3 
49.4 
32 
0 
.0 
32 
.0 
6.6 
32 
.0 
20.0 
/OO 
e /B /e BO 34- 38 SB 
Fig. 1.—Curves showing summaries of infection ratings on the roots, tiller bases, and aboveground parts 
of Goldcoin wheat plants inoculated with Ophiobolus graminis , when grown in soil containing 56.1 per 
cent of moisture, and held at different temperatures, as shown in Table II 
