240 THE APPLE 



cut in fine pieces and dissolved in warm water. The cost of the 

 soap varies from 5 to 20 cents per pound. 



Kerosene emulsion. When properly made and diluted, this 

 material proves very satisfactory in checking the work of the 

 aphis. It must be carefully prepared, however, else it will burn 

 the foliage severely. The formula is kerosene, 2 gallons ; water, 

 1 gallon ; soap, \ pound. 



Heat the water and dissolve the soap in it. Add the kerosene 

 and churn or mix forcibly with a force pump for ten minutes. The 

 mixture should be smooth and creamy, and will adhere to a glass 

 surface. Dilute in the proportion of 1 part emulsion to 10 parts 

 water before applying to foliage. 



Black Leaf 40. Black Leaf 40 is a tobacco extract and may be 

 purchased from dealers in spraying supplies or from seed houses. 

 Directions for diluting are given on each bottle. It is easily and 

 quickly applied, and seems bound to become the popular aphis 

 spray for summer use. 



Paris green. Paris green is fast going out of use in orchard work 

 because of the free arsenious oxide which it contains. The danger 

 of burning the foliage is too great to justify its use. 



Commercial arsenate of lead. At present arsenate of lead is 

 used more than any other poison for leaf-feeding and fruit-infesting 

 insects. It can be bought from any of the insecticide companies 

 and from local dealers at prices varying from 7 to 20 cents per 

 pound. It should not cost over 8 cents in 100-pound lots, and 

 small growers will do well to combine their orders in buying. 



The commercial paste varies in water content from 25 to 50 per 

 cent. It is guaranteed 12 per cent arsenic acid (As o 5 ), and may 

 run as high as 20 or 25 per cent. It should not contain more than 

 .75 per cent soluble arsenic. 



It can be had in the powdered form, about 1 per cent water and 

 25 per cent arsenic acid, but is usually preferred as a paste, as 

 it stays in suspension better and is more adhesive. Care should 

 be taken when it is purchased in quantity to keep up the water 

 content. It does not burn the foliage, and its only disadvantage 

 is that it is relatively slow-acting. 



Homemade arsenate of lead. Arsenate of lead can be made at 

 home by using acetate lead, 1 1 ounces ; arsenate soda, 4 ounces ; 



