INSECTICIDES, FUNGICIDES AND DISINFECTANTS 213 



The compounds of copper have decided poisonous effects 

 upon the lower organisms. 



161. Insecticides for Biting Insects. Lead ar senate 

 may be purchased in the form of a thick paste or dry powder. 



FIG. 71. Pail spray for small herds. (Farmers' Bulletin, U. S. 



Dept. Agr.) 



It is prepared by the action of lead nitrate or lead acetate 

 on crystallized disodium hydrogen arsenate. It contains 

 little or no soluble arsenic and, for this reason, is especially 

 applicable to plants with tender foliage. Lead arsenate is 

 applied in suspension in water or in combination with fungi- 

 cides by means of a spray, usually at the rate 2 to 7 pounds 



