August, '21] 



LATHROP AND BLACK: WESTERN PEACH BORER 



331 



Experiments In Control 



Our observations of the winter habits of the root borer larvae, led 

 us to investigate the possibility of applying some substance during 

 fall or winter which would destroy the larvae in their winter cells and 

 possibly those which remained in the superficial burrows. A series 

 of tests were applied as follows: 



Plot 1. Scalecide 1 pt. 



Water 7 qts. 



Plot 2. Scalecide 1 pt. 



Sodium Arsenate 2 ozs. 



Water 7 qts 



Plot 3. Scalecide 1 pt. 



Nicotine Sulfate 40% 3 ozs. 



Water 7 qts 



Plot 4. Nicotine Oleate 5 ozs. 



Water 7 qts. 



Plot 5. Nicotine Resinate 3 ozs. 



Water 7 qts. 



Plot 6. Check. No treatment 



Plot 7. Fuller's Earth' 5 lbs. 



Nicotine Sulfate 40% X lb. 



Plot 8. Sulfur dust 5 prts 



Lead arsenate (powder) 1 pt. 



Tobacco dust 4 prts. 



The soil was removed from the base of each tree to the depth of four 

 to six inches. A generous amount of the liquid or dust was then ap- 

 plied and the soil replaced about the tree. 



In no case was there a satisfactory control, and these substances do 

 not seem promising. This failure does not necessarily indicate that 

 treatment at this time is inapplicable, but some more satisfactory lar- 

 vicide must be found before the treatment will be effective. 



MisciBLE Oil - Sodium Arsenate vSprays 



The fact that the young larvae spend a considerable period in the 

 outer bark led us to hope that by using a soluble arsenate with miscible 

 oil as a carrier, the corticular region of the bark might be so thoroughly 

 saturated with poison as to kill the larvae as they worked in this re- 

 gion. 

 For this purpose the following formula was used. 

 ^Miscible Oil No. 1. 1 pint. 



Sodium arsenate 2 ounces 



Water to make two gallons 



'A commercial spray oil prepared by General Chemical Co., San Francisco, Cal. 



