EXPERIMENT STATION BULLETINS. 289 



FORMULAS. 



Bordeaux Mixture. 



Copper Sulphate 4 pounds 



Fresh Lime (unslaked) 4 pounds 



Water 40 gallons 



Cai-e should be taken that the lime is of good quality and well burned 

 and that it has not become air-slaked. If only a small amount is to be 

 slaked it will be best to use boiling water, and the lime should not be 

 allowed to become dry while slaking. When much Bordeaux is to be pre- 

 pared, it is a good plan to make up stock solutions which can be mixed as 

 required, proceeding- as follows: Dissolve 40 pounds of copper sulphate 

 in 40 gallons of water and in a box slake 40 or more pounds of lime. These 

 can be kept for some time, but it is best not to prepare more than can be 

 used in a week or ten days. Each gallon of the solution will contain one 

 pound of the copper sulphate, and in preparing it for spraying, as many 

 gallons should be used as are necessary to furnish the proper amount of 

 copper sulphate. Thus for each 40 gallons required, four gallons of the 

 solution should be placed in a barrel in which there are 16 gallons of 

 water. An equal weight of lime, as near as can be estimated, should be 

 placed in another barrel and 20 gallons of water added to this. After 

 being well stirred, the lime mixture should be allowed to stand for a 

 minute to give the coarse particles time to settle, and then the lime water 

 should be dipped out and slowly poured into the copper sulphate solution, 

 stirring rapidly as the lime water is pOured in. The mixture is then ready 

 for use, but, as there is danger of burning tender foliage if the amount of 

 lime is insufficient, it is well to use some simple test, such as dipping a 

 knife blade in the mixture, or adding a few drops of ferro-cyanide of 

 potassium (yellow prussiate of potash). If the amount of lime is not 

 sufficient, copper will be deposited upon the knife blade, while the ferro- 

 cyanide of potassium will give the mixture a deep brownish-red color. 

 More lime should be added if necessary until no discoloration is caused in 

 either case. A slight excess of lime will do no harm and is always 

 desirable. 



The copper sulphate can be easily dissolved, if suspended in the water in 

 a coarse sack or basket. If the lime is properly slaked and is handled as 

 recommended, there will be little trouble from lumps, but it is always well 

 to strain the lime-water through a sieve, such as a piece of window 

 screening. 



This is the best remedy for fungous diseases except while the trees are 

 dormant, or as the fruit is ripening. It is especially valuable for use with 

 Paris green and other arsenites, as it lessens the danger of their injuring 

 the foliage and the washing effect of rains. 



Copper Sulplwte Solution. 



Copper Sulphate 1 pound 



Water 25-50 gaUons 



For use before the buds open the above solution is fully as effectual as 

 Bordeaux mixture and is easier to prepare and apply, but it should not be 

 applied to any plant after the buds have opened. For use against the 

 37 



