Mar. 22, 1924 
Nematode Disease Caused by Tylenchus tritici 
929 
plat with 45 per cent of its weight in galls. The resulting stands and 
yields are given in Table III. 
Table III. —Number of plants and culms and weight of grain from Turkey wheat unin¬ 
fested with galls and infested at seeding time with different quantities of galls , together 
with reduction in stand and yield and, percentage by count of galls in threshed grain 
from inoculated plats at Madison , Wis., in IQ 22 
Plants. 
Culms. 
Grain. 
Percent¬ 
Percentage by weight of galls 
sown in seed. 
Number. 
Percent¬ 
age of 
reduc¬ 
tion. 
Number. 
Percent¬ 
age of 
reduc¬ 
tion. 
Weight 
grams). 
Percent¬ 
age of 
reduc¬ 
tion. 
age by 
count 
of galls 
in grain. 
1,215 
105 
3 > 33 ° 
2m C20 
935 
695 
O 
2A 
26 
67 
7 
15. 
400 
1,375 
59 
425 
cr 
20 
310 
74 
94 ° 
72 
220 
76 
30 
Fig. i.—G raph comparing the results of determining by different methods the percentages of nematode 
disease infection in different varieties of wheat as shown in Table II. 
There seemed to be a consistent relation between the quantity of 
infecting material used and the resulting reduction in the stand. Fromme 
(jo) found a similar relation between the percentage of galls in the seed 
and the resulting severity of infection. 
Estimates of reduced yield due to nematode injury, based on the 
number of seedlings showing symptoms of such injury, are inaccurate, 
because it was found that many plants showing such symptoms as seed¬ 
lings did not always produce galls at maturity. Eighty plants showing 
typical symptoms of nematode injury were tagged as seedlings at the 
Arlington Experiment Farm in April, 1919, and at maturity 15 of them, 
