94 Report of State Board of Horticulture. 



cautiously and only in sufficient amount to insure thorough 

 slaking. After thorough slaking more water can be added 

 and stirred in until it has the consistency of thick cream. 

 When both are cold pour the lime into the diluted copper so- 

 lution of required strength, straining it through a fine mesh 

 sieve or gunny cloth, and thoroughly mix. 



It is then ready for use. Considerable trouble has fre- 

 quently been experienced in preparing the bordeaux mixture. 

 Care should be taken that the lime is of good quality and well 

 burned, and has not been air slaked. Where small amounts 

 of lime are slaked it is advisable to use hot water. The lime 

 should not be allowed to become dry in slaking, neither should 

 it become entirely submerged in water. Lime slakes best 

 when supplied with just enough water to develop a large 

 amount of heat, which renders the process active. If the 

 amount of lime is insufficient, there is danger of burning 

 tender foliage. In order to obviate this the mixture can be 

 tested with a knife blade or with ferro-cyanide of potassium 

 (one ounce to five or six ounces of water) . If the amount of 

 lime is insufficient, copper will be deposited on the knife 

 blade, while a deep brownish-red color will be imparted to the 

 mixture when ferro-cyanide of potassium is added. Lime 

 should be added until neither reaction occurs. A slight ex- 

 cess of lime, however, is desirable. 



The bordeaux mixture is best when first prepared. Stock 

 solutions of lime and copper can be made and mixed when 

 required. 



SPRAY NO. 8— BORDEAUX MIXTURE WHEN TREES ARE IN FOLIAGE. 



3 pounds of sulphate of copper. 

 6 pounds of lime. 



50 gallons of water. 



SPRAY NO. 9— COPPER SULPHATE SOLUTION. 

 (Strong solution for dormant trees). 



1 pound of copper sulphate. 

 25 gallons of water. 



SPRAY NO. 10— COPPER SULPHATE FOR SUMMER SPRAY. 



4 ounces of copper sulphate. 

 50 gallons of water. 



