20 
BULLETIN" 842, U. S. DEPARTMENT OF AGRICULTURE. 
WATEE-SOAKED GALLS. 
A glance at the results presented in Table I, obtained from treat- 
ing galls previously soaked, shows that the larvae are only slightly 
affected by an immersion of as much as 15 minutes in water at 46°, 
48°, and 50° C, respectively. They are completely killed, however, 
when exposed for 30 minutes or more in water heated to 50° C. Al- 
most identical results secured by the writer after subjecting another 
parasitic nematode, Heterodera radicicola, to the same treatments 
suggest that other plant-attacking nematodes may respond similarly. 
Table I. 
-Effect of hoi-water treatment on larvcc of tlie toheat nematode in- 
closed in wet galls. 
Hot-v 
•ater treatment. 
Larva' active 
;per cent). 
Number 
of galls, 
each con- 
taining an 
average 
of more 
than 1,500 
Extent of 
observa- 
In each gall at lasl 
examination. 
Average- 
Lot. 
Date, 
1918. 
Temper- 
ature 
(°C.). 
Duration. 
tion after 
treatment 
(days). 
In 
In 
each 
treat- 
ment. 
larvee. 
1 
2 
3 
4 
5 
6 
each 
lot. 
Minutes. 
No. 15 
6 
Mar. 18 
46 
5 
2 
90 
50 
90 
SO 
95 
80 
80.83 
80.83 
No.14 
5 
...do 
46 
10 
2 
75 
10 
1 
75 
75 
47.2 
47.20 
No. 13a 
6 
...do 
46 
15 
2 
90 
2 
10 
90 
60 
100 
58. 66 
5S.66 
No. 13 
6 
...do 
48 
5 
2 
90 
90 
90 
85 
60 
80 
82.5 
82.50 
No. 12 
6 
...do 
48 
10 
2 
90 
90 
90 
90 
50 
85 
82.5 
82.50 
No. 11a 
6 
...do 
48 
15 
2 
85 
85 
75 
50 
70 
75 
73.33 
73. 33 
No.9 
6 
...do 
50 
5 
3 
75 
65 
40 
85 
85 
75 
70. &3 
70.83 
No. 8 
6 
...do 
50 
10 
4 
10 
2 
4 
70 
75 
30 
31.83 
31.83 
Nio. 17 
6 
Mar. 22 
50 
15 
3 
90 
85 
90 
85 
95 
10 
75.83 
75.83 
No. 18 
6 
...do 
50 
20 
3 
90 
70 
95 
85 
95 
45 
80 
40.00 
No. 2 
6 
Mar. 13 
50 
20 
3 







No. 19 
6 
Mar. 22 
50 
25 
3 
85 
75 
80 
65 
90 
30 
70.83 
70.83 
No. 23 
5 
Mar. 25- 
50 
30 
4 








No. 24 
5 
...do 
50 
35 
4 








No. 25 
2 
...do 
50 
40 
4 




No. 26 
5 
...do 
50 
45 
4 







No. 11 
6 
Mar. 18 
52 
5 
4 
45 
30 
40 
50 
30 
60 
44.16 
44.16 
No. 10 
6 
...do 
52 
10 
7 

40 
35 
1 
1 
60 
22.83 
JlS.l 
No. 20 
6 
Mar. 22 
52 
10 
4 


.26 
80 


13. 37 
No. 21 
6 
...do 
52 
15 
4 


.13 
.5 
.26 
85 
14.3 
No. 27 
5 
Mar. 25 
52 
15 
5 


.26 


.51 
• 3.7 
No. 40 
6 
Apr. 6 
52 
15 
6 







No. 44 
5 
Apr. 16 
Mar. 22 
52 
15 
6 







No. 22 
6 
52 
20 
4 







No. 28 
5 
Mar. 25 
52 
20 
4 


o 



• 
No. 39 
6 
Apr. 6 
52 
20 
6 


o 




No. 45 
5 
Apr. 16 
52 
20 
6 






No. 29 
3 
Mar. 25 
52 
25 
4 




}» 
No. 38 
5 
Apr. 6 
Mar. 13 
52 
25 
6 







No.l 
6 
54 
10 
3 







No. 30 
5 
Mar. 25 
54 
10 
5 




.49 
.OS 
| .02 
No. 35 
6 
Apr. 6 
54 
10 
6 







No. 41 
5 
Apr. 16 
54 
10 
6 






j 
No.5 
6 
Mar. 13 
54 
15 
3 







| 
No. 31 
5 
Mar. 25 
54 
15 
9 




.2 
.04 
1 .01 
No. 36 
6 
Apr. 6 
54 
15 
6 







No. 42 
5 
Apr. 16 
54 
15 
6 






No. 37 
6 
Apr. 6 
54 
20 
6 







No. 43 
5 
Apr. 16 
54 
20 
6 







No. 34 
5 
Apr. 4 
56 
5 
8 







No. 32 
5 
...do 
C6 
10 
8 







No. 33 
5 
...do 
56 
15 
8 







No.3 
6 
Mar. 13 
5S 
5 
3 








No.4 
6 
...do 
58 
10 
3 








No.6 
6 
...do 
60 
5 
3 








Check 
6 
...do 
C 1 ) 
2 
Days. 
2 
95 
95 
95 
95 
95 
95 
95 
95 
Do 
6 
Mar. 20 
0) 
8 
8^ 
95 
95 
95 
95 
95 
95 
95 
95 
i Room temperature. 
