Mar. 22, 1924 
Nematode Disease Caused by Tylenchus tritici 
93i 
for as many as five galls may replace a single kernel. Likewise, the 
percentage by weight is inadequate, as the galls are very light in com¬ 
parison with the kernels. 
The relative volume of galls and kernels, while far from being an ideal 
or accurate basis for estimating reductions in yield, seems to be the most 
nearly adequate. In order to determine accurately the reduction in 
yield, it is necessary to compare the yields of infected and uninfected 
crops grown under parallel conditions. Limited data of this kind 
were obtained for rye in connection with another experiment. These 
results are given in Tables VII and VIII. 
Thus far the nematode disease of cereals has not been reported from 
any part of the spring-wheat region. Experiments were conducted at 
the Arlington Experiment Farm in 1920 to determine how this disease 
would affect spring wheat. In March 3-rod rows of each of 13 varieties 
of spring wheat were sown in soil which had been heavily inoculated with 
galls during the previous October and also in soil to which galls were 
applied at the time of seeding. Two rows of each variety were sown on 
clean soil at the same time. No infection occurred in the uninoculated 
control rows, but unfortunately these plants were destroyed by sparrows 
before harvest to such an extent that reliable yield data could not be 
secured from them. 
The percentage of seedling injury in the inoculated rows was deter¬ 
mined by noting the number of diseased plants per 100 in three rep¬ 
resentative parts of each row. At maturity the plants from each set 
of rows were threshed and the percentages of galls in the grain by num¬ 
ber, volume, and weight were determined. The results are given in 
Table V. 
Table V .—Percentages of diseased seedlings and percentages of galls by number , volume, 
and weight in the threshed grain of different varieties of spring wheat grown on soil 
inoculated with galls in the fall arid on soil inoculated at time of sowing in the spring 
at the Arlington Experiment Farm in 1920 
Variety. 
Cl. 
No. 
Fall-inoculated soil. 
Spring-inoculated soil. 
Seed¬ 
ling 
infec¬ 
tion. 
Galls in threshed grain. 
Seed¬ 
ling 
infec¬ 
tion. 
Galls in threshed grain. 
Num¬ 
ber. 
Vol¬ 
ume. 
Weight. 
Num¬ 
ber. 
Vol¬ 
ume. 
Weight. 
Per 
Per 
Per 
Per 
Per 
Per 
Per 
Per 
cent. 
cent. 
cent. 
cent. 
cent. 
cent. 
cent. 
cent. 
Amautka. 
4064 
32 
30 
13 
7 
46 
63 
40 
27 
Baart. 
1697 
50 
41 
21 
13 
85 
97 
93 
90 
Dicklow.. 
3663 
60 
36 
16 
13 
8s 
96 
92 
95 
Hard Federation. 
4733 
80 
24 
11 
S 
96 
99 
99 
99 
Haynes Bluestem. 
2874 
30 
9 
3 
3 
70 
95 
88 
83 
Kota. 
S878 
33 
30 
14 
7 
80 
87 
7 i 
63 
Kubanka. 
1440 
24 
37 
16 
9 
70 
88 
74 
71 
Marquis. 
3641 
33 
8 
4 
2 
70 
81 
60 
48 
Monad. 
3320 
16 
69 
44 
32 
70 
82 
64 
55 
Pentad (D-5). 
3322 
37 
63 
66 
26 
68 
81 
62 
50 
Power. 
3697 
56 
37 
19 
14 
83 
95 
92 
91 
Prelude.. 
4323 
90 
80 
61 
40 
98 
99 
96 
94 
Ruby. 
6047 
60 
32 
20 
11 
95 
99 
88 
82 
Average.. 
46 
38 
24 
14 
78 
89 
78 
73 
