516 PREVENTION AND DESTRUCTION OF INSECT PESTS. 



Spray in early morning and late in the afternoon, unless on dull days. 

 Never spray when the blossom is out, as it kills the bees. Never leave 

 the wash ahont, as it is poisonous. Three sprayings should he alioays 

 employed — one just before the huds begin to burst, the second just be- 

 fore the blossom opens, and the third directly the blossom has fallen. 

 By so doing several insect attacks are dealt with, such as Winter 

 moth, Tortrix, and Codling moth. 



2. Tobacco waslies. — Tobacco is one of the most potent insecticides. 

 It may either be used in the form of a wash or mixed with camphor 

 and used as a fumigant under glass. In many cases rag or paper 

 steeped in tobacco-juice is used for burning in glass-houses to kill 

 aphis, thrips, &c. It is best used as nicotine, but this is too ex- 

 pensive to use on a large scale. Nicotine wash is made as 

 follows : — 



Nicotine (90-98 per cent) . . 1 oz. 



Soft-soap . . . . . 2 oz. 



Water ... .10 gallons. 



Plain tobacco-leaf waste may also be used, or home-grown tobacco, 

 as follows : — 



Tobacco waste .... 2-3 lb. 



Soft-soap ..... ^-1 lb. 



Water ..... 10 gallons. 

 Infuse the tobacco waste in water, and press ; then add a pinch of 

 soda, and add the whole to the dissolved soap and water. At 

 present the only way tobacco wash can be used commercially is 

 to buy it from insecticide makers. 



3. Paraffin washes. — Parafiin-oil or kerosene forms an excellent 

 insecticide and insectifuge, especially if it is used with soft-soap in 

 the form of an emulsion, by which the paraffin is evenly distributed 

 in the water. This wash is useful for celery fly, marguerite fly, 

 scale insects, plant-lice, &c. Paraffin emulsion may be prepared by 

 mixing equal proportions of boiling soft-soap solution and paraffin 

 together, and thoroughly churning them until a thick creamy emul- 

 sion is formed. This emulsion can be kept and mixed with sixteen 

 to thirty times its bulk of warm water when required for use. An- 

 other method is to dissolve 1 quart of soft-soap in 2 quarts of 

 boiling soft water. Remove from the lire, and while stiU boilino- 

 hot add one pint of paraffin oil, and immediately churn the mixture 

 with a small hand syringe for five minutes. For use dilute with 

 ten times its volume of water (Cousins). By far the best mixture is 

 paraffin jelly, made as follows : Paraffin, 5 gallons ; soft-soap, 8 lb. ; 



