44 INSECT PESTS OF FARM, GARDEN AND ORCHARD 



pests of the orchard and garden. Arsenate of lead remains in 

 suspension rather better than Paris green and is exceedingly 

 adhesive, remaining on the foliage for two or three months. 

 Arsenate of lead is made from arsenate of soda and acetate of 

 lead or nitrate of lead, and may be made by the user if desired, 

 but owing to the varying composition of these chemicals when 

 purchased on the open market and the fact that the manufactured 

 article can now be purchased in quantity practically as cheap as 

 it can be made, its home manufacture is not recommended, and 

 is now but rarely practiced. The market price of arsenate of 

 lead has varied widely, owing to strong competition, but usually 

 sells at from 8 to 10 cents per pound in 100-pound kegs, and at 

 20 cents for single-pound packages. 



Arsenate of lead is now made in a powdered form for dusting 

 on crops where spraying is impracticable or unsatisfactory. Most 

 of that manufactured in powdered form is crystalline and will 

 not mix as readily with water as the paste, and is therefore not 

 recommended for use with water. One manufacturer, however, 

 is producing an amorphous powder, which is bolted like flour, and 

 which mixes readily with water, and may be used exactly the 

 same as the paste, of course using approximately only half as much 

 weight for the same effectiveness, as half of the paste is water. 



4. Arsenite of lead is a compound very similar to the arsenate, 

 which is made from sodium arsenite, but it contains less arsenic 

 and usually much more soluble arsenic, for which reason its use 

 has not proven satisfactory, and is rarely sold by reliable dealers. 



Used in Water. The above arsenicals are generally diluted 

 with water and applied as a spray, which is usually much the 

 most efficient method. Where Bordeaux mixture or lime- 

 sulfur is to be sprayed on fruit trees or garden crops for the 

 control of fungous diseases, the arsenical may be added to them 

 at the same rate as to water. The combination of arsenicals 

 with other common fungicides is not usually possible without 

 danger of serious injury to the foliage. 



Used as Dust. Under some circumstances the arsenicals are 

 more readily applied in the dust form. Dusting may be done 



