237 



of this procedure being proved by the high quality of the Canadian 

 and Tasmanian fruit which is sent over to be sold in British markets, 

 due to the thorough methods taken in those countries to prevent 

 damage by insects. 



Formulae for standard wetting mixtures are given, to any of which 

 the particular poison required to control a specific pest may be added. 

 These are : — a resin stock solution made by dissolving 8 lb. washing 

 or crystal soda in 3 gals, of water in a large vessel and boiling. While 

 boiling, 8 lb. block or lump resin roughly powdered is gradually 

 added, and when dissolved, more water is added until the quantity 

 is made up to 10 gals. This should be diluted with nine times its bulk 

 of water before using. Other solutions are made by dissolving 10 lb. 

 soft soap or 7 lb. bar or hard soap in 100 gals, of soft or rain water and 

 diluting 1 in 10 before using. 



For winter washes 1 quart creosote oil or crude disinfectant, which 

 makes a milky mixture with water, may be added to the resin stock 

 solution in the proportion of 1 in 40 of the oil and 1 in 16 of the 

 disinfectant. This is an effective spray against apple suckers. For 

 a caterpillar wash or against codling moth {Cydia pomonella) and 

 weevils lead arsenate may be added to the standard wash. Sodium 

 arsenate 1| lb. and lead acetate or nitrate 3| lb. should be dissolved 

 separately in water and then mixed together and sufficient water 

 added to make the quantity up to 30 gals. One gallon of this mixture 

 added to one gallon of stock solution and made up to five gallons 

 makes an effective spray. It must be well stirred before use. 

 Potassium bichromate may be substituted for sodium arsenate and 

 should be used in the proportion of 2^ lb. of bichromate to 5 lb. lead 

 acetate or nitrate. 



For woolly aphis {Eriosoma lanigerum) a very successful spray 

 may be made by adding 1 pint of carbon tetrachloride to 3 gals, of 

 stock solution and 1 oz. creosote oil, the whole beuig diluted in the 

 proportion of 1 to 7. Methylated spirit or petrol may be substituted 

 for the tetrachloride, but is less effective. 



Red spider on gooseberries may be controlled by spraying with 

 a mixture of 3 lb. flowers of sulphur added to 10 gals, resin stock 

 solution, while hot, and then diluted in the proportion of 1 : 8. The 

 stock solutions diluted with water only are the best control sprays 

 for Aphids. 



Griddle (N.). Precipitation in Relation to Insect Prevalence and 

 Distribution. — Canadian Entomologist, London, Ont., xlix, no. 3, 

 March 1917, pp. 77-80. 



Humidity, chiefly in the form of rain or snow, is instrumental in 

 either aiding or curtailing the spread of insects all over Canada, par- 

 ticularly in the Prairie Provinces. Most insects are very dependent 

 on the presence of moisture, especially in the larval stages. An example 

 of insects that thrive best when moisture is least prevalent is the 

 Rocky Mountain locust {Melanoplus spretus), which has caused enor- 

 mous losses in past years and has invaded Manitoba on more than 

 one occasion. It has always invaded Western Canada during a drv 

 season, arriving in swarms in July and August. Eggs were soon 

 deposited in vast numbers, and crops suffered in consequence much 



