APPENDIX I 671 



the proportion of water, but the formula given above has been regarded as the 

 standard with which all others should be compared, at least in experimental work. 

 The 5-5-50 Formtda. — Here the preparation consists of 



Copper sulphate, 5 pounds. 



Lime, 5 pounds. 



Water to make 50 gallons. 



The use of this formula is desirable where the purity of the lime is in doubt, as 

 it makes certain, with lime of any reasonable quality, that all of the copper is properly 

 neutralized. The danger of scorching, or russeting fruit is, therefore, less. With- 

 holding I pound of the copper sulphate also cheapens the mixture by a few cents. 

 For these reasons the 5-5-50 formula has come to be quite generally used in orchard 

 spraying. In fact, it has almost replaced the old standard Bordeaux mixture in 

 spraying for the apple scab, bitter-rot, pear and cherry leaf-blight and similar diseases. 



The 4-4-50 and Other Formulas.— The strength of the mixture is often further 

 reduced by using the 4-4-50 formula, but it is questionable whether it pays to reduce 

 the strength. For use as a whitewash, a very concentrated mixture, 6-4-20, may 

 be desirable and for certain diseases Bordeaux mixture can be diluted so as to be 

 equivalent to 6-4-100. 



The form of Bordeaux mixture most harmless to foliage is 3-9-50, having a con- 

 siderable excess of lime. This may be known as the "peach Bordeaux mixture." 



Various modifications of the original Bordeaux mixture have been suggested and 

 tried. The principal ones, however, are the "soda Bordeaux mixture" and the 

 "potash Bordeaux mixture." The former consists of 6 pounds of copper sulphate, 

 2 pounds of caustic soda and 50 gallons of water. The latter is the same except an 

 equal quantity of caustic potash is substituted for the soda. Other materials are 

 sometimes added to Bordeaux mixture to increase its spreading power. The most 

 successful is ordinary hard soap, dissolved in hot water and added at the rate of 4 

 pounds to the barrel, and this modified Bordeaux mixture is known as "soap 

 Bordeaux." 



Bordeaux Resin Mixture (N. Y. (Geneva) Bull. No. 188, 1900). 



Resin, 5 pounds. 

 Potash lime, i pound. 

 Fish oil, I pint. 

 Water, 5 gallons. 



Add to Bordeaux as directed below. To prepare a stock resin solution proceed 

 as follows: "Place the oil and resin in the kettle, heating them until the resin is dis- 

 solved, then remove the kettle from the fire and allow the mass to cool slightly, after 

 which the solution of lye is added slowly, the whole being stirred while adding the 

 lye. After adding the lye the kettle should be again placed over the fire and the 

 required amount of water added. The whole should be boiled until the solution 

 will mix with cold water forming an amber-colored solution. Care should always 

 be taken to have the resin and oil cool enough, so that when the solution of lye or the 

 water is added the whole mass will not boil over and catch fire. 



