158 DECIDUOUS FKUIT INSECTS AND INSECTICIDES. 



results to use a power outfit at a high pressure and a coarse drenching 

 spray to penetrate the lichens and the heavy scale incrustation. A 

 power sprayer is especially useful in applying distillate-oil emulsion, 

 crude-oil emulsion, and mechanical mixtures of either, as a hand outfit 

 does not give sufficient agitation for a perfect emulsion. 



The writer recently noticed several prune orchards which had been 

 sprayed with a commercial distillate spray and caustic soda at 4 per 

 cent strength; they were well cleaned of the scales and lichens. 



COST OF SPRAYING. 



Table IV shows the comparative cost of materials of the most im- 

 portant and efficient treatments. To get the total cost of spraying 

 it will be necessary merely to add the cost of the labor, which is vari- 

 able and was therefore not included. Usually 3 men and a team 

 are required for spraying with a hand pump and the same number 

 with a power outfit, adding an additional man and team where a 

 supply wagon is used. 



The number of trees that can be sprayed in a day is variable, 

 depending upon the size of the trees, the availability of the water, and 

 the efficiency of the labor. With medium-sized prune trees, from 800 

 to 1,000 trees is considered a good day's work with a power outfit 

 and a supply tank. 



Below is shown what the ingredients of the spray mixtures would 

 cost the fruit grower in the vicinity of San Jose in barrel lots: 



Lime (unslaked) per barrel . . $1. 75 



Sulphur (flour) per 100 pounds . . 2. 65 



Caustic soda, in 120-pound cases per pound . . . 05 \ 



Borax, in 12-pound cases 1. 40 



Lye, in 48-pound cases . 3. 25 



Fish oil, in barrel lots per gallon . . .35 



Crude oil (12 to 24° Baume), in 110-gallon drums 3. 00 



Distillate oil (28° Baume), in 110-gallon drums per gallon. . . 07-. 09 



Commercial lime-sulphur solution per barrel. . a 10. 00 



Commercial distillate-oil emulsion do. . . . a 7. 50 



Commercial distillate emulsion and caustic soda do a 9. 95 



A good fish-oil soap can be made at the following cost: 



Lye, 2 pounds $0. 1354 



Fish oil, 1^ gallons 5250 



Water, 6 gallons. 



This makes $0.6604 for 40 pounds of scrap, or $0.0165 per pound. 

 The concentrated distillate-oil emulsion (55 per cent) will cost: 



Hot water, 12 gallons. 



Fish-oil soap, 30 pounds $0. 495 



Distillate oil (28° Baume), 20 gallons 1. 400 



Total 1. 895 



This makes $1,895 for 36 gallons, or $0.0526 per gallon. 



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