REPORT OF THE HORTICULTURIST 125 



SESSIONAL PAPER No. 16 



EXPERIMENTS IN DESTROYINQ APHIS WITU KEROSEKE EMULSION MADE WITH FLOUR. 



It having be^^n discovered and demonstrated at the Central Experimental Farm 

 that kerosene emulsion could be made with flour instead of soap for holding the kero- 

 sene in suspension, this form of emulsion was used successfully in a practical way in 

 1905 and 1906. As the emulsion made in this way is much easier to make than with 

 soap it was desirable to learn what porconta^-e of oil was necessary to kill the aphis, 

 as soap in addition to its value in holding the kerosene in emulsion is an insecticide 

 itself and without it more kerosene might be required. The following percentages of 

 kerosene were, therefore, used on July IG, 1900, in spraying apple trees badly infested 

 with aphis. Percentages used, approximately: G per cent, 7i per cent, 9 per cent, 11 

 per cent. 



The following notes were made: — 



Kerosene Emulsion with — 



6 per cent kerosene — Aphis not affected. 



li per cent kerosene — Aphis not affected. 



9 per cent kerosene — Not so effective as 11 per cent but most of the aphjs 



destroyed. 

 11 per cent kerosene — Practically all aphis destroyed. 

 In the kerosene emulsion made with soap scarcely 7 ^per cent kerosene is recom- 

 mended. 



There was no injury to the foliage of the trees in any case. Apple trees in 

 nursery were sprayed on July 12, with very good results, the insects being nearly all 

 killed. 



Plum trees were sprayed Julv 5 and July 13 with 11 per cent kerosene emul- 

 sion. "Many aphis were killed without apparent injury to the trees. 



The Norway Spruce hedges were found to be badly attacked with a species of 

 aphis and on July 26. 27 and Aug. 1, there were about 400 gallons of kerosene emr^lsion 

 (11 per cent kerosene) vised in spraying the hedges with the result that the aphis were 

 destroyed. It was necessary to saturate the trees with the emulsion, holding the nozzle 

 close in so that the spray would envelop the branches as many of the aphis were hid- 

 den. The pmAilsion did not injure the spruce to any extent where the foliage had not 

 been already v/er-kened by the aphis. 



Experiments with Different Methods of ^Preparing the Flour Emulsion. 



Experiments had been conducted in the chemical laboratory in conjunction with 

 Mr. Frank T. Rhutt, Chemist, who discovered the value of flour in making kerosene 

 emulsion, to determine the weight of flour necessary to hold in suspension certain 

 quantities of kerosene. Experiments had also been tried in different methods of pre- 

 paring the emulsion and the amount of churning necessary. This work being done 

 with small quantities it remained to determine the best method when made by the 

 barrel. 



A dasher was made by nailing two cross-pieces to one end of a pole, the other 

 end being used as a handle. A piece of sacking with a hole in the centre for the pole 

 to go through held in place on the barrel by a hoop prevented the emulsion from 

 eplasliing out of the barrel. 



To make an emulsion having approximately 11 per cent of kerosene (or to be 

 exact. 11% per cent) it was necessary to have 4.i gallons oil to 36 pallons of water. 



In making the emulsions the kerosene was put in the barrel first, the flour then 

 poured in and usually mixed well with the kerosene by stirring for a short time with 

 a stick. Twenty gallons of water were then added and then the whole mass churned 

 violently with the dasher \n an up and down motion for tlie required length of time. 

 "Wlien the churning was done the rest of the water was added until the barrel was 

 filled- 



