426 



STATE BOARD OF AGRICULTURE. 



treatment of onr last experiment, was a normal one, it was decided to 

 repeat this part of the experiment. 



EXPERIMENT VIII. 



March 9, 1914, dissected out a number of egg masses and placed them 

 in 1-1000 Hg CK for two minutes. The egg masses were then transferred 

 to drops of agar on four cover glasses, and sealed down over four cul 

 ture slides. The results of this experiment are given in Table VIII. 



TABLE VIII.— ACTIVE LARVAE FOUND. 



Treatment March 9, 1914. 



March 10. 



March 11. 



March 12. 



March 13. 



HgCl2 1-1000 

 HgCl2 1-1000 

 HgCls 1-1000 

 HgCh 1-1000 



Very many 

 Very many 

 Very many 

 Very many 



Very many Abundant All quiet 



Abundant Abundant All quiet 



Used for cjulturing expe riment. 

 Used for CiUlturing experiment. 



The results of this experiment appeared to verify those of the pre- 

 vious experiment, and to show that a short exposure to 1-1000 Hg CI 2 

 does not keep the nematode eggs from hatching. 



As it now seemed probable that the various chemicals exerted an in- 

 hibitory effect in closed vessels, it was decided that data should next 

 be obtained on treatments conducted under conditions more nearly like 

 those present in the soil of the field experiments. To accomplish this, the 

 egg masses Avere placed after treatment in tubes of agar, closed only by 

 cotton plugs. A synthetic agar medium was prepared by adding one and 

 two-tenths per cent of powdered agar and one per cent of glucose to 

 Pfeflfer'g nutrient plant solution. This on being sterilized and cooled, 

 solidified into a solid medium, through which one could easily see. A 

 number of tubes of this medium were prepared, using about ten c. c. to 

 a tube. 



EXPERIMENT IX. 



March 14, 1914, dissected out a large number of egg masses from root- 

 knots and divided them into twelve lots. After treatment, each lot was 

 transferred to a tube of synthetic agar while it was still wet with the 

 solution in which it had been treated. 



1. Placed the first lot in 1-100 solution of 40% formaldehyde for a 

 few minutes. 



2. Placed the second lot in 1-25 solution of 40% formaldehyde for a 

 few minutes. 



3. Placed the third lot in 1-10 solution of 40% formaldehyde for 

 a few minutes, 



4. Placed the fourth lot in full strength 40% formaldehyde for a few 

 minutes. 



5. Placed the fifth lot in 1-500 Hg Cl„ for a few minutes. 

 0. Placed the sixth lot in 1-200 Hg CL for a few minutes. 



7. Placed the seventh lot in 1-100 Hg CI, for a few minutes. 



8. Placed the eighth lot in full strength ''Black Leaf 40" for a short 

 time. 



9. Placed the ninth lot in full strength lime-sulfur, 31-32° B., for a 

 few minutes. 



