424 



STATE BOARD OF AGRICULTURE. 



8. Treated the eiglitli lot iu carbon bisulphide vapor for 17 hours. 

 The results of this experiment are given in Table V. 



TABLE v.— ACTIVE LARVAE OBSERVED. 



February 10, 1914, all of the plates of the above series were cleaned 

 up except the 1-100 solution of 40% formaldehyde. This plate was ob- 

 served from time to time to see how long the larvae w^ould remain alive. 

 March 30, 1914, active larvae were observed. 



EXPERIMENT VI. 



February 28, 1914, dissected out many egg masses and divided them 

 into four lots. After treatment, each lot w^as transferred to a plate of 

 potato agar, and the plates sealed shut with paraffin. 



1. Treated the first lot by rinsing it in boiled tap water. 



2. Treated the second lot in 1-100 solution of 40% formaldehyde for 

 3 minutes. 



3. Treated the third lot in 1-25 solution of 40% formaldehyde for 3 

 minutes. 



4. Treated the fourth lot in 1-10 solution of 40% formaldehyde for 3 

 minutes. The results of these experiments are given in Table VI. 



TABLE VI.— ACTIVE LARVAE OBSERVED. 



As the conditions under which these laboratory experiments were be- 

 ing conducted differed greatly from those in the field, it was concluded 

 that possibly one or more of these factors was influencing the results, 

 thus making the laboratory results very inconclusive. Perhaps the most 

 obvious difference between the laboratory and the field experiments was 

 the surroundings of the nematodes .and eggs after treatment. In the field 

 experiments the eggs were in the soil where plenty of air and moisture 

 could get to them to dilute the various chemicals applied. In the labora- 

 tory experiments the eggs were enclosed in petri dishes which tended to 

 keep out the air and moisture, and to keep in the volatile chemicals. This 

 was €specially true when the plates were sealed with paraffin. If petri 

 dishes did act as an important factor in causing the chemicals to in- 



