NEMATODE DISEASE OF WHEAT. 



25 



Table IV. — Effect of formaldehyde, mercuric chlorid, copper sulphate, and 

 sulphuric acid on nematode larvce inclosed in water-soaked galls. 



Chemical and temperature. 



Strength. 



Expo- 

 sure. 



Date, 



1918. 



Number 

 of galls 

 treated. 



Average 



larvae 

 living in 

 each lot 

 (percent). 



Formaldehyde: 



At room temperature (about 21" C). 



Mercuric chlorid. 



Copper sulphate. 



Sulphuric acid. 



At50°C 



At52°C 



At room temperature (check) 



Check. 



1: G40 



1: 320 



1: 100 



1: 100 



1: 100 



1: 80 



1: 50 



1: 50 



1: 25 



1: 320 



1: 320 



Tap water 

 1: 1,000... 



2: 1,000. 



4: 1,000. 



2 

 4 

 2 

 4 

 2 



4 

 2 



2 

 4 

 2 



Minutes. 

 1 

 2 

 4 

 1 

 2 

 4 

 Days. 



4 



Hours. 

 3 

 4 

 5 

 6 

 7 



17 

 3 

 4 

 5 

 6 

 7 



17 

 3 

 4 

 5 

 6 

 7 



17 

 3 

 4 

 5 

 6 

 7 



17 

 7 



17 

 7 



17 

 7 



17 

 7 



17 

 7 



17 

 7 



17 

 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 

 Ijune 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. 



