18 THE REPORT OF THE No. 36 



vestigations have been conducted against the Green Apple Aphis, in order to 

 determine the clieapest spray to apply ; and against Apple Scab where different 

 mixtures, strengths, and formulae have been used in test against each other. The 

 Codling Moth field work has also been in the hands of the Provincial Horticultural 

 authorities, working in association with the officers of the Entomological Branch. 

 Approximately 333 acres of apple orchards were handled under quarantine in the 

 neighbourhood of Vernon during tlie ])ast year. 107 acres of this 333 were infested 

 with Codling Moth in the year previous, 116 acres were contiguous to ihe infested 

 area and were treated as though infested. 11,433 apple trees in this acreage were 

 Ijanded and were sprayed three times, and at the end of the season 19,401 boxes 

 of apples were individually examined for larvae Altogether 373 larvae and pupae 

 of the Codling Moth were taken at Vernon, and as Vernon, during 1919, was the 

 only point in the Okanagan Valley where examples of this moth were taken, the 

 control operations have succeeded to a very creditable degree. A few years ago 

 three distinct and separate outbreaks of the moth occurred in the Okanagan Valley, 

 with as many as 10,000 larvas ]>eing taken in a single yea.T. The record as it stands, 

 therefore, is not only very^ encouraging but is an indication that incipient outbreaks, 

 in small areas, with proper support by the growers, can be not only reduced but 

 also eradicated. A small new outbreak of this pernicious pest occurred at North 

 Bend this year, which will necessitate action this coming year. 



The Tent Caterpillars, Mahcosoma pluvialis and M. erosa were exceedingly 

 common at Vancouver and Victoria in 1919. The outbreak at certain points being 

 exceptionally severe. A memorandum outlining the method for control was sub- 

 mitted to the City Councils of the Cities of Vancouver and Victoria, but with this 

 exception, these insects were studied exclusively by Mr. Baird. 



Many sundry insect notes were collected during the course of the year and 

 the more important minor records have been incorporated in a report to the Depart- 

 ment of Agriculture, Victoria, B.C. A similar report for the year 1918 was sub- 

 mitted in the same way to the Provincial Department of Agriculture and was 

 published in two sections in the official organ of the Department, the Agricultural 

 Journal. 



RESULTS OF SOME PRELIMINARY EXPERIMENTS WITH 



CHLOROPICRIN. 



G. J. SpenceE;, 0. A. College, Guelph. 



In 1917, when meditating upon the effects of enemy gas that I had received 

 at Passchendaele it occurred to me that British gas might be turned upon enemies 

 other than Germans. 



The opportunity to try this out came in the spring of 1919 when the Khaki 

 L^niversity of Canada obtained permission for men of the Canadian forces to study 

 at British Universities. I went to Victoria University, Manchester, where through 

 the courtesy of Prof. S. J. Hicksou, I was given the run of the research laboratory 

 and the insectaries at Fallowfield. From the explosives department of the Ministry 

 of Munitions I obtained samples of three of our common battle gases, one of them 

 being chloropicrin, formula tri-chlor-nitrite. 



It was decided to try the effects of these gases with a view to greenhouse, 

 flour-mill and domestic fumigation. There was time to carry out only one experi- 

 ment in Manchester before I was recalled to camp. 



