ly 



Water, 3 pints. 



Dissolve the soda and resin in the water by heating. 

 While boiling add water slowly until the whole makes 

 36 pints. To use add 8 parts of water to 1 part of the 

 above Stronger mixtures have been used, but may do 

 injury when not carefully applied. 3 pints of the com- 

 pound to 4 of water is about the maximum to be used 

 with safety. 



Mr. Coquillett, an agent of the Division of Entomology 

 at Washington, has also worked with this compound and 

 gives the following as the result of his experiments with 

 one of the scale insects of fruit trees in California. 



Caustic soda (70 per cent), 9 lbs. 



Resin, 30 lbs. 



Fish oil, 4i lbs. 



Water, enough to make 100 gallons. 



He advises the use of a kettle holding 30 gallons for 

 making the compound. All the materials are plq,ced in 

 this and after covering them to a depth of 4 or 5 inches 

 with water, they are dissolved and then boiled for two 

 hours, or " until it will dilute evenly with water, like 

 black coffee. " At this stage the kettle is slowly filled 

 with water and when full may be emptied into a tank or 

 barrel where the remainder of the water can be added. 

 Any sudden chilling of the preparation by the addition 

 of large quantities of water is, he says, to be avoided. 

 It would seem from Mr. Coquillett's work that the com- 

 pound destroys the insects by forming a sort of varnish 

 on their bodies thus choking up their breathing pores 

 and smothering them. The soda is useful consequently 

 only by virtue of its action in the resin and oil, and 

 no more should be employed of this ingredient than 

 is necessary, because of injuries to foliage when the 

 proportion used is large. 



On our west coast the use of gas for destroying scale 



