EXPERIMENT STATION BULLETINS. 269 



FORMULAS. 



BORDEAUX MIXTURE. 



Copper Sulphate 2 to 4 pounds 



Fresh Lime (unslaked) 4 to 6 pounds 



Water 50 gallons 



Care 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 

 prepared, 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 60 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 solu- 

 tion 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 re- 

 quired, 2 to 4 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 insuflScient, it is well to 

 use some simple test, such as dipping a knife blade in the mixture, or add- 

 ing 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 mix- 

 ture a deep brownish-red color. More lime should be added if neces- 

 sary until no discoloration is caused in either case. An excess of lime 

 will do no harm and is always desirable. 



The copjjer 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. 



