270 Apple and Pear Stielier 



completely block the stigmata, rosin being a solid thing. The soap 

 solution has two defects: 



(1) It is of use only in case of buds where the leaves are not 

 exposed to the wind and the sun. 



(2) The larvae may and generally do recover from the effects 

 of a soap solution after some hours. 



The results of the soap solution were (the solution being 1 %) : 

 72 % dead. 28 % living. 



In order to remove these two defects the creosote oil was emulsified 

 with it — the oil being poisonous to the insects. These several experi- 

 ments were tried with differing percentages of the oil, that of the soap 

 (solution) being constant. 



(1) With 1-10 or -1% of creosote. 

 22500 cc. water 



8 oz. soap Spraying 2.30 p.m., 24. 5. 13. 



22^ cc. creosote oil 

 The result being : 



39 living \ 

 74 dead 



106 dead 

 54 living 



■Nearly 50 % dead. 



(2) With -2 % of creosote. 



4 oz. soap 



11200 cc. water Sprayed at 12.30 p.m. 



22 cc, creosote 



110 dead K, , no n/ j j 

 ,. . Nearly 93 % dead. 



8 living J 



(They were dead next day.) 



(3) With -25 % of creosote. 



(There were three trials. Every time 

 the result was that all the 

 larvae were killed by the time 

 of the examination. 



11200 cc. water 

 28 cc. creosote 



(a) The method of the examination. The observers (Prof. Lefroy, 

 Mr Davidson, Mr Miles and myself) used to wheel the machine to the 

 apple trees. One of the heavily infected apple trees was selected and 

 was sprayed with the driving jet. Each of us then broke the twigs at 

 random and collected them together. Those twigs were brought home 

 and spread in an open space on papers. When they were fully dry 

 Prof. Lefroy picked out the dead and the living larvae, and thus the 

 different results and the percentages were obtained. 



The creosote oil is very harmful to plants and especially to tender 

 leaves. It was tested iu those percentages used in tlie experiments 



