MONTANA EXPERIMENT STATION. 261 



INSECTICIDES AND FUNGICIDES. 



Arsenate of Lead. 



This valuable insecticide is rapidly coming to the front as a 

 safe and reliable arsenical poison. It can be applied to the foliage 

 in any desired strength without injury, and when applied remains 

 through rain storms. Its white color may be detected on the leaves 

 thereby serving as a guide in its application. It is made by the 

 union of acetate of lead and arsenate of soda, both being soluble in 

 water. It is no longer necessary for the user to make his own arsen- 

 ate of lead for it is now being sold at reasonable prices by the Bow- 

 ker Insecticide Co , Boston, Mass., and Wm. H. Swift, Boston, Mass. 



Paris Green. 



Paris green is an old, well-known arsenical insecticide. It was 

 first brought to prominence in connection with the war that was 

 waged against the Colorado potato-beetle in the western states be- 

 tween i860 and 1870 



In spraying with this substance a hot day should be avoided if 

 possible, especially it it is desired to apply nearly to the limit of what 

 the foliage will stand without injury. The water on the foliage soon 

 becomes warmed and when warm dissolves the Paris green more 

 rapidly, thereby resulting in injury to the leaves. 



Arsenite of Lime. 



The desire for a reliable and cheaper arsenical insecticide has 

 led to the employment of a product resulting from the union of 

 freshly slacked lime and commercial white arsenic. The propor- 

 tions are : 



Commeicial white arsenic i pound. 



Unslacked lime 2 pounds. 



Water 2 gallons. 



Boil together for twenty minutes to half an hour. As soon as 

 the arsenic is dissolved it is precipitated by the lime as insoluble 

 arsenite of lime. There is danger however that not all the arsenic 

 will be precipitated out as it is difficult to tell when all has been 



