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Vegetable-oil soap was as effective in making the boiled emulsions 

 as fish-oil soap. 



Emulsions made from oils with viscosities below 80, have not shown 

 uniformly good kill of scale. There were apparently no differences in 

 effectivness on San Jose scale in emulsions made from oils of 90 to 220 

 viscosity. 



Tests with boiled potash-fish-oil-soap emulsions in summer showed 

 very little injury to apple foliage, considerable injury to peach, and to a 

 few other plants under some conditions. Due to the difficulty in reaching 

 the scale when the trees are in foliage, summer sprays are not recom- 

 mended except in case of very severe scale infestation. 



Where oil emulsions were properly mixed and applied, no injury 

 to trees has resulted. 



On the basis of these experiments and observations, the following 

 recommendations are made : 



1. Oil emulsion is recommended as a cheap and effective spray for 

 the control of San Jose scale. The formula for the stock emulsion found 

 best in our experimental work is as follows : 



Oil 1 gallon 



Potash-fish-oil-soap 1 to 2 pounds 



Water Ya gallon 



Heat to boiling, and pump twice at a pressure of 75 pounds, or more. 

 The strength recommended is 2.4% (3 gallons in 100), or, in case of se- 

 vere and increasing infestation, 4 gallons in 100 gallons of water. The 

 best oil to use, judging by our experiments and those of investigators in 

 Indiana and Arkansas, is a lubricating oil coming within the following 

 limits : 



Specific gravity.. .87 to .9,3 at 20° C. 



Volatihty Not above 2% at 110° C. for 4 hours. 



Viscosity 90 to 250 seconds (Saybolt test) at 100° F. 



2. If cold-mixed emulsions are used, they may be made according 

 to the following formulae: — • 



Bordeaux, Cold-mixed 



Pump together equal parts of oil and 4-4-50 Bordeaux mixture, 

 sending the material at least three times through the pump. 

 For a 2% strength, dilute four gallons in one hundred. 



Calcium Caseinate, Cold-mixed 



Pump together two gallons of oil and one gallon of water in 

 which is dissolved four ounces of calcium caseinate. For a 

 2% strength, use three gallons in one hundred. 



