FUNGICIDES. 



1. BORDEAUX MIXTURE 



4 pounds copper sulphate (blue vitriol). 

 4 pounds lime (unslaked). 

 25-50 gallons water. 



Dissolve the copper in hot or cold water using a wood or earthern 

 vessel. Slake the lime in a tub, adding the water cautiously and 

 only in sufficient amount to insure thorough slaking. After 

 thoroughly 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 solution of required strength, straining 

 it through a fine mesh sieve or a gunny cloth and thoroughly mix. 

 The standard mixtures are : 



(a). 25 gallons (full strength solution, or 4-4-25 formula). 



(b). 50 gallons, (half strength mixture, or 4-4-50 formula). 



It is then ready for use. Considerable trouble has frequently 

 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 (i oz. to 

 5 or 6 oz. 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 excess of lime, however, is desirable. 



The Bordeaux Mixture is best when first prepared. Stock solu- 

 tions of lime and copper can be made, and mixed when required. 



