ARSENITE OF ZINC 421 



solved in one gallon of water. The dry powder should first be 

 mixed with a little water to form a thick paste before the other 

 ingredients are added. The mixture should then be boiled until 

 dissolved. Care must be exercised in handling this and other 

 similar poisons. This solution may be kept to mix with water or 

 Bordeaux mixture as needed. When spraying for diseases and 

 insects combined, mix one quart of this stock solution with 50 

 gallons of Bordeaux mixture containing plenty of lime. If water is 

 used in place of Bordeaux mixture, use two quarts of the stock 

 solution to fifty gallons of water and add two pounds of lime 

 slaked and diluted to the consistency of cream. 



Paris green is a common commercial form of arsenical poison. 

 It varies somewhat in its composition, but should contain from 50 

 to 58 per cent of arsenous oxide. To avoid danger of burning 

 the leaves when spraying with this material, lime should be added 

 to the mixture at the rate of one or two pounds to 50 gallons. In 

 spraying potatoes,- it is usually used at the rate of eight ounces of 

 Paris green to 50 gallons of water. For apples, one-half this 

 amount of poison is used. 



Arsenate of lead is a poison more easily combined with lime- 

 sulfur in its different forms. It is more adhesive than Paris green, 

 and is seldom known to cause injury to the foliage. It is coming 

 to be the most popular poison for use in spraying orchards. Com- 

 mercially this poison is prepared in two forms: As thick paste, 

 and as a powder. If the paste form is used, allowance must be 

 made for the water it contains, which is about 50 per cent of its 

 weight. Five pounds of the paste to 100 gallons of water or 100 

 gallons of lime-sulfur is used in spraying apples. On the peach we 

 may use four pounds of the paste with 100 gallons of lime-sulfur 

 or 100 gallons of water. As much as eight or ten pounds to 100 

 gallons of water may be used in fighting the rose beetles on grape 

 vines. As such a strong solution is very bitter, it may be sweet- 

 ened by adding two gallons of molasses to each hundred gallons 

 of liquid. It is difficult to get the powdered arsenate of lead to 

 mix readily with water, but if it is fine enough to do so, the above 

 proportions may be reduced one-half, as the powder is twice as 

 strong as the paste. 



Arsenite of zinc is a light powder which is coming to be used 

 by vegetable growers and others in place of arsenate of lead. It 

 should seldom be mixed with water alone because of the injury to 

 leaves. Lime or Bordeaux mixture may be used to prevent this 



