December, '11] METCALF: SPRAYING FOR GLOOMY SCALE 



COUMERCIXL— Concluded 



519 



Insecticides 



Strength 



Time 



Winter I 



Spring II I Summer III 



Scalime . 



San-U-Zay. 



Bogart's sulphur compound. 



Pratt's carbohne. 



1-5 

 1-8 

 1-25 



1-10 

 1-12 

 1-30 



1-5 

 1-8 

 1-25 



1-25 



poor 

 poor 



excellent 

 good 



fair 

 fair 



fair 



fair 

 fair 



Home-made 



Pure Kerosene, tested for its killing properties. 



Kerosene emulsion: 40% . 

 50%. 

 60%. 

 30%. 



Cotton Oil emubion (Cooley's formula) . . 

 Linseed Oil emulsion (Cooley's formula). 



Carbolic Kerosene Emulsion 



1 lb. soap, 

 30 gals, water, 

 3 gals, kerosene, 

 3 gals, carbolic acid (crude). 



Kerosene emulsion made as usual with the addition of the carbolic acid, and the whole thoroughly emulsified. Ill poor. 



The trees used for these experiments were inspected and the relative 

 state of their infestation was ascertained as carefully as possible before 

 commencing the spraying. After the trees were sprayed, they were 

 inspected at intervals of two or three months for a year and a half. 

 In this way we were able to determine not only the immediate effects 

 upon the trees, but also the results on the tree as a whole. In making 

 our inspection more attention was paid to the relative benefits to 

 the whole tree than to careful counts and estimates of the per cent 

 of scale killed. 



Roughly speaking "excellent" in the above report means above 95 



