INSECTICIDES AND EQUIPMENT FOR CONTROLLING INSECTS 7 



Home-made bordeaux mixture should be freshly prepared when 

 used. Ready-prepared mixtures are available on the market. 



This spray has a blue color and leaves a bluish- white deposit on 

 sprayed surfaces. Its sticking properties are excellent. It is used 

 as a control for the potato leafhopper on potato and as a repellent 

 for flea beetles on various vegetable and flowering plants. Bordeaux 

 mixture is essentially a fungicide and as such is often combined with 

 various insecticides such as nicotine, lead arsenate, calcium arsenate, 

 and others. 



It is also used as a safener for lead arsenate on apple foliage and 

 as an emulsifier for tank mixtures of lubricating-oil sprays on dor- 

 mant apple, pear, quince, prune, plum, and peach trees. 



Various formulas for making bordeaux mixture are used. The 

 following is one that is often recommended : 



For 100 gallons For small quantities 



Copper sulfate (bluestone) 8 pounds. 4 ounces. 



Fresh hydrated lime 12 pounds. 6 ounces. 



Water_I 100 gallons. 3 gallons. 



On tender plants that would be injured by the above spray it is 

 advisable to use half the quantities of copper sulfate and lime indi- 

 cated in the formula. 



When used as a safener for lead arsenate on apples, it may be 

 reduced in strength to y 2 or % pound of copper sulfate with 1 or iy 2 

 pounds of lime, respectively, per 100 gallons. The use of bordeaux 

 mixture on apple foliage should be avoided in cool, wet weather, 

 since under such conditions it may cause severe russeting of fruit. 



Powdered copper sulfate is preferable to the crystal or lumpy forms 

 for use in making bordeaux mixture, since it is readily soluble in cold 

 water. When power sprayers are used the required quantity of the 

 powdered copper sulfate is poured, or washed through a screen, into 

 the partly filled sprayer in which the agitator is kept running. After 

 the copper sulfate is completely dissolved, the lime is added either as 

 a dry powder or in the form of a water-mixture. The remainder of 

 the required quantity of water is then added to the tank and the 

 agitation maintained while this is done. When small quantities are 

 needed for use with compressed-air or knapsack sprayers, the total 

 quantity of water to be used is divided and placed in two pails. The 

 powdered copper sulfate is dissolved in one pail, and the lime mixed 

 with the water in the other. Then the copper sulfate solution and the 

 lime-water mixture are poured together and thoroughly mixed. 

 The mixture is then poured through a strainer into the sprayer. If 

 copper sulfate crystals or lumps are used, they should preferably be 

 dissolved in a quantity of hot water representing one-half the total 

 volume desired. If hot water is not available, place the copper 

 sulfate crystals in a cloth sack and suspend this in the vessel con- 

 taining cold water in such a way that the bottom of the sack is 

 just below the surface of the water. Complete solution should occur 

 in 1 to 2 hours. The suspension of lime in the other half of the 

 water is then added, as the mixture is being agitated, and the whole 

 poured through a strainer into the sprayer. 



For convenience or where large quantities of bordeaux mixture 

 are needed, stocks of copper sulfate solution and lime suspension may 



