386 



Pomona College Journal of Entomology 



PROPORTIONS 



We followed closely the directions laid down by R. S. Woglum and so 

 used the chemicals in the following proportions: 



Sodium cyanide 1 dry weight. 



Sulphuric acid 1>4 liquid " 



Water - 2 



Some have recommended using 1 of acid instead of Ij^j, which will make a 

 little saving, but which we considered too small to again change our apparatus. 



SCHEDULES 



Sodium cyanide, containing much more available hydrocyanic acid gas, 

 is more powerful as an insecticide than potassium cyanide. The amount 

 is therefore cut down 25% less thart the potassium. For a purple scale 

 dosage we cut Woglum's Schedule No. 1 just 25%, and for black scale cut the 

 potassium cyanide purple scale dosage 25%. It simply means that with three- 

 fourths of a pound of sodium cyanide, as much efficiency may be obtained 

 as from a full pound of the potassium cyanide. Accordingly a large number 

 of schedules as per accompanying cut were printed for use in fumigating 

 black scale. (Figure 133.) 



HORTICULTURAL COMMISSIONER 



FUMIGATING SCHEDULE FOR BLACK SCALE 

 SODIUM CYANIDE 



Figure 133. Sodium Cyanide Schedule for Black Scale. 



