944 
Journal of Agricultural Research Vol. XXVII, No. 12 
below the seed: 15, 12, 10, 8, 6, 4 and 2 inches, respectively. Three 
controls were sown. In one, galls were placed with the seed at the time 
of sowing; in another they were strewn on the surface of the ground 
immediately after sowing; and in a third no inoculum was used. With 
the exception of the three controls, the galls were placed in the soil on 
April 15, and the wheat was sown a week later. Three weeks after 
sowing, the seedlings in the two inoculated controls showed symptoms 
of nematode injury. Five weeks after the time of sowing, some infested 
plants were found in the frame in which galls had been placed two inches 
below the seed. No vegetative symptoms were observed in the plants 
in any of the other frames although galls were found in a number of the 
heads at harvest time, as shown in Table XV. 
Table: XV. — Percentage of infected heads of Prelude wheat resulting from placing galls 
in the soil at various depths in relation to the seed, Madison , Wis., IQ22 
Heads of wheat. 
Location of galls in relation to seed. 
Exam¬ 
ined. 
Infected. 
Healthy. 
Shat¬ 
tered. 
Total. 
Percent. 
Control without galls. 
90 
0 
0 
80 
10 
Galls on surface. 
Galls with seed ». 
80 
49 
61 
26 
5 
Galls 2 inches below seed. 
54 
17 
32 
37 
0 
Galls 4 inches below seed. 
44 
26 
59 
14 
4 
Galls 6 inches below seed. 
35 
7 
20 
23 
5 
Galls 8 indies below seed. 
30 
5 
17 
21 
4 
Galls 10 inches below seed. . 
75 
41 
55 
28 
6 
Galls 12 inches below seed. 
69 
15 
22 
36 
18 
Galls 15 inches below seed. 
70 
0 
0 
50 
20 
0 Plants injured so badly in the seedling stage that no heads were produced. 
Invasion by the nematodes probably occurred at so late a stage that 
head infection took place very shortly after the larvae reached the plants. 
It is evident from the high percentages of infected heads in the frames 
in which the galls had been buried 10 and 12 inches below the seed that, 
although some of the larvae are killed at the greater depths, many are 
able to travel upward through a foot of compact soil to reach the host 
plants. This fact proves the futility of deep plowing of the stubble 
as a control measure. 
TRANSMISSION THROUGH BIRDS AND ANIMALS 
To what extent the larvae of Tylenchus tritici survive passage through 
the digestive tract of birds and farm animals has long been a debated 
question. Marcinowski (17) fed galls to sparrows, goldfinches, pigeons, 
chickens, mice, gophers, and marmots. She collected and examined the 
excreta and found some live larvae in all except that from the chickens, 
gophers, and marmots. She succeeded in infecting wheat plants by 
placing the droppings of the goldfinches with the seeds sown. She con¬ 
cluded, however, that inasmuch as the birds took the galls very unwill¬ 
ingly and only when no other food was available, birds are a minor 
factor in the spread of the nematodes. 
In 1921, E. R. Kalmbach, of the Bureau of Biological Survey, United 
States Department of Agriculture, working in cooperation with the 
writer, fed galls containing adults’ eggs, and larvae of Tylenchus tritici 
