NEMATODE DISEASE OE WHEAT. 
25 
Table IV. — Effect of formaldehyde, mercuric chlorid, copper sulphate, and 
sulphuric acid on nematode larvw inclosed in water-soaked galls. 
Chemical and temperature- 
Treatment. 
Strength. 
Expo- 
sure. 
Date, 
1918. 
Number 
of galls 
treated. 
Average 
larvae 
living in 
each lot 
(percent). 
Formaldehyde: 
At room temperature (about 21° C. 
At50°C 
At52°C 
At room temperature (check) 
Mercuric chlorid. 
Copper sulphate . 
Sulphuric acid. 
Check . 
1: 320. 
1: 100. 
1: 100. 
l: 80.. 
1: 50.. 
1: 50.. 
1: 25.. 
1: 320. 
1: 320. 
Tap water . 
1: 1,000. 
2: 1,000. 
10: 1,000.. 
5 per cent . 
10 per cent 
15 per cent 
J per cent . 
1 per cent . 
It per cent 
Tap water 
f 2 
I 4 
f 2 
I 4 
f 2 
I 4 
2 
4 
r 2 
l 4 
2 
4 
r 2 
I 4 
Minutes. 
! I 
! ! 
Days. 
Hours. 
Days. 
Mar. 22 
...do... 
...do.... 
...do.... 
...do.... 
...do.... 
Apr. 3 
...do 
Mar. 22 
...do.... 
Apr. 3 
...do 
...do.... 
...do.... 
Apr. 17 
...do 
...do.... 
...do.... 
...do.... 
...do.... 
/Mar. 22 
\Apr. 3 
Oct. 19 
...do.... 
...do.... 
...do.... 
June 4 
June 3 
Oct. 19 
...do.... 
...do.... 
...do.... 
June 4 
June 3 
Oct. 19 
...do.... 
...do.... 
...do.... 
June 4 
June 3 
Oct. 19 
...do.... 
...do.... 
...do.... 
June 4 
June 3 
Apr. 4 
...do... 
...do... 
...do... 
...do... 
...do... 
...do... 
...do... 
...do... 
...do... 
...do... 
...do... 
|..do.... 
{Oct. 19 
[June 3 
It appears, therefore, from a study of the results presented in 
Table IV that the nematode in protected galls does not readily 
succumb to formaldehyde and will survive treatments with this 
chemical which seriously impair the germination of the wheat. 
