34 Nebraska Agricultural Exp. Station, Research Bui. 12 
pressure of the solution surrounding the roots rendered them 
very susceptible indeed. 
Table 8 shows that the older tissues are the most suscep- 
tible to infection. A number of inoculations were also made 
in roots of young trees in jars. It was found that one-year-old 
roots became infected with difficulty and then only when near 
the surface of the soil. In such infections the growth of the 
mycelium was very slow. Mycelial growth in the region of 
the crown of the tree progressed more rapidly in young than 
Table 8 — Rate of growth of mycelium above and below 
inoculations in roots 
Inoculated 
in Xylem 
Inoculated 
at Cambium 
VARIlilTY 
Above 
1 
Below 
Above 
Below 
Inches | 
Inches 
Inches 
1 Inches 
24.0 1 
31.5 
22.0 
1 2 6.0 
21.5 1 
20.0 
18.5 
^ 4.0 
37.0 1 
25.0 
14.0 
1 ion 
I IJ.o 
48.5 ] 
51.0 
8.0 
1 11.0 
37.5 1 
46.5 
17.0 
1 15.5 
42.0 
31.5 
7.5 
1 6.5 
Ben Davis 
58.5 1 
29.0 
12.5 
1 10.0 
3.0 1 
11.0 
1.5 
j 2.0 
3.0 1 
3.5 
2.0 
1 2.0 
2.0 
2.5 
4.0 1 
1.5 
l!5 
1 i!o 
14.0 1 
13.5 
11.5 
1 16.0 
21.0 1 
20.5 
14.0 
1 10.5 
11.0 I 
15.0 
Average 
1 1 
.| 23.39 
21.62 
10.15 
1 10.77 
2.0 1 
2.5 
2.0 
1 3.0 
3.0 1 
3.0 
2.0 
1 3.5 
3.5 1 
6.5 
3.0 
1 3.5 
3.5 1 
5.0 
1.5 
1 1.5 
18.0 1 
26.5 
3.5 
1 5.0 
21.0 1 
16.0 
1.0 
1 1.5 
42.5 1 
36.0 
3.5 
1 2.0 
Jonathan 
2.0 1 
4.0 
3.0 
1 3.0 
10.5 1 
11.5 
2.5 
1 2.5 
6.0 1 
7.0 
2.b 
1 1.0 
8.5 1 
12.0 
1.5 
1 1.0 
3.0 1 
1.5 
5.5 1 
4.5 
10.0 1 
6.5 
14.0 1 
7.5 
Average 
1 1 
.| 10.20 1 
10.00 
2.36 
1 2.50 
