316 PRINCIPLES OF ECONOMIC ENTOMOLOGY 

 For small quantities use: 



Paris green 1 heaping teaspoonful 



Lump lime 2 or 3 ounces 



Water 3 gallons 



For dry application the powdered Paris green may be 

 mixed with flour or air-slaked lime and dusted upon the 

 plants by enclosing the powder in a muslin sack and shaking 

 this over the plants it is desired to treat. 



London purple is a by-product in the manufacture of 

 aniline dye and is an effective poison but somewhat less 

 certain in its effect and more likely to injure foliage. It is 

 at ])resent not so common on the market as Paris green, it 

 is, however, somewhat cheaper and when properly diluted 

 is a desirable insecticide. 



Arsenate of Lead. — Arsenate of lead, available in two forms 

 — paste or as a white powder — may be secured on the market, 

 or the arsenate may be formed by chemical combination of 

 arsenic and lead. Formulse for the use of this substance 

 are as follows: 



Arsenate of lead (paste) 3 to 10 pounds 



Water 50 gallons 



or 



Arsenate of lead (powder) 1 to 4 pounds 



Water 50 gallons 



For small quantities use: 



Arsenate of lead (paste) 1 teaspoonful 



Water 1 gallon 



If used as a spray this can be applied to a great variety of 

 plants for the destruction of leaf-eating insects, and since 

 it can be used at high strength without injury to foliage it 

 may be used for the most resistant kind of insects. Its killing 

 power is not equal to that of Paris green and consequently 

 somewhat stronger solutions must be used. 



Like Paris green, it may be used in the dr}' form as dust 

 or with a powder gun. 



Hellebore. — Hellebore is a white powder destructive to 

 insects but not poisonous to domestic animals or man, unless 



