INSECTICIDES. 285 



poTsoj^s. (for biting insects.) 



Most of the poisons used as insecticides are composed 

 of compounds of arsenic. Formerly only Paris green and 

 London purple were used. Now several substitutes are 

 cheaper and some more desirable. Therefore, where the 

 word ar senile has been used above, any of the arsenites 

 mentioned below may be used, except as qualified. 



Remember that these poisons are all dangerous to human 

 life. Keep them well labeled and locked up. 



Arsenites. 



Unless otherwise directed above, the arsenites may be 

 either sprayed or dusted. Dusting is usually desirable on 

 low-growing j^lants only and should be done in the early 

 morning while damp with dew. "When used dry tlie 

 arsenite is usually mixed with land plaster or flour and is 

 applied with a bellows, perforated can, or powder-gun. 



When adding a dry arsenite to water for spraying, first 

 mix it in a small quantity of water, so as to form a paste. 



Paris Green. 



Paris green . 1 pound 



Water 160-200 gallons 



Lime 2 pounds 



When used with Bordeaux mixture use 4 ounces of 

 arsenite to 50 gallons of the mixture. Keep well stirred 

 while spraying. 20 to 25 cents per pound. 



empty barrel, stirring constantly. A "stock solution" of copper 

 sulphate, in which 40 pounds is dissolved in 40 gallons of water, is 

 convenient for extensive work. Four gallons should then be diluted 

 with one-half barrel of water and mixed with lime as above. 



