82 BULLETIX 351^ U. S. DEPAKTAIEXT OF AGEICULTUEE. 



power outfit was used as in applying the cottonseed-oil sprays. The 

 oil was emulsified in the same way as kerosene in making kerosene 

 emulsion. This oil at 20 per cent gave an efficiency of from 93 to 

 100 per cent, but the injury to the trees was severe. It did far less 

 injuiy, however, than any other of the oils used at this strength. 

 This experiment shows that raw Imseed oil was a promising oil and 

 that it should be used at a much decreased strength. 



Experiment 2 was performed on March 19, 1913, by spraying a 

 vigorous 2-year-old tree at Washington, D. C, with a 10 per cent 

 emulsion of raw linseed oil. This spray was apphed very thor- 

 oughly ^vith a hand sprayer at the time the buds were swelling. 

 Every scale upon this tree was killed and there was no spray injury. 

 The experiment shows that it is feasible to apply a 10 per cent emul- 

 sion to 2-year-old trees in the spring without injm'y. 



Experiment 3 demonstrated that a 5 per cent emulsion of raw 

 linseed oil will destroy more than 80 per cent of the scales upon 

 12-year-old trees, provided the application is made in the spring 

 before the buds open. In experiment 4 the fonnula used differs 

 from the one used in No. 3 in that gasoline was substituted for one- 

 half of the oil. The scale count gives nearly the same efficiency for 

 this expeiiment as for the preceding one. This experiment shows 

 clearly that gasoline increases the efficiency of the spray. Experi- 

 ment 5 was made by spraying 200 moderately vigorous 12-year-old 

 peach trees at ]\Iidvale, Pa., November 5, 1913, at which date the 

 trees had just finished shedding their leaves. An emulsion con- 

 taining 5 per cent raw linseed oil and 3 per cent gasofine was apphed 

 with a power sprayer, furnishing 175 to 200 pounds pressm'e, and 

 equipped with angle nozzles having apertines of one-sixteenth inch. 

 The efficiency upon well-sprayed branches was 100 per cent and there 

 was no spray injur}^. 



Experiments 4 and 5 show that an emulsion containing 5 per cent 

 raw linseed oil and 3 per cent gasoline will effectively control the 

 .terraj)in scale without injmy to the trees. While expeiiment 5 

 shows that linseed oil gives good results in the fall, the author recom- 

 mends that tliis oil be apphed in the spring just before the buds open. 



Cost of Linseed Oil. 



At the date of writing this paragraph hnseed oil sold in Wash- 

 ington, D. C, for 50 cents per gallon in barrel lots, and gasoline at 

 13 cents per gallon. The cost of this spray, exclusive of the labor of 

 making it, would be about 3 cents per gallon. 



5 gaUons raw linseed oil, at 50 cents $2. 50 



3 gallons gasoline, at 13 cents 39 



2 pounds laundi'y soap, at 5 cents 10 



92 gallons water 



100 gallons 2.99 



