658 INSECTS AFFECTING VEGETATION 



Mississippi Valley the 4-5-50 formula has given good results, espe- 

 cially in dry years. 



The 4-4-50 and Other Formulas. The strength is often still 

 further reduced by using a 4-4-50 formula, but it is questionable 

 whether it pays to reduce the strength. The same result can be se- 

 cured with sprays having less copper, provided the application is 

 thorough and repeated; but, as in actual experience the cost of ap- 

 plying Bordeaux mixture is often from two to five times the cost of 

 the mixture itself, economy demands the use of the strongest mixture 

 which will do the work without injury to the plants. 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. 



Peach Bordeaux Mixture. The form of Bordeaux mixture most 

 harmless to foliage is made up by the formula 3-9-50, having a con- 

 siderable excess of lime. This may 'be known as peach Bordeaux 

 mixture, and contains ingredients as follows: 



Copper sulphate 3 pounds 



Lime 9 pounds 



Water to make 50 gallons 



Modified Bordeaux Preparations. Various modifications of the 

 original Bordeaux mixture have been suggested and tried. The prin- 

 cipal ones, however, are the soda Bordeaux mixture and the potash 

 Bordeaux mixture. The former consists of 6 pounds of copper sul- 

 phate, 2 pounds of caustic soda, and 50 gallons of water. The latter 

 is the same except that an equal quantity of caustic potash is sub- 

 stituted for the soda. Other materials are sometimes added to Bor- 

 deaux 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. (F. B. 243.) 



Method of Making Bordeaux Mixture in Small Quantities. 

 Where only a small quantity of Bordeaux mixture is required from 

 a bucketful to a barrel gives good results. Two half-barrel tubs are 

 made by sawing a barrel through the middle. One tub is used for 

 the bluestone solution and the other for the milk of lime, and each 

 tub should contain 23 to 25 gallons. One man dips the bluestone 

 solution with a bucket and pours it into a barrel or other vessel, and 

 another man simultaneously dips up and pours in bucketfuls of the 

 milk of lime. The lime solution should 'be kept well stirred. If only 

 a single barrel is to be made, the materials may be dissolved in the 

 dilution tubs, but if a number of lots are required the materials can 

 be kept in stock solution and simply transferred by dipping. In 

 preparing very small quantities of Bordeaux mixture, buckets of 

 similar vessels may be substituted for the half-barrel tubs. It is pos- 

 sible for a single operator to dip a bucketful of the bluestone solution 

 and then a bucketful of milk of lime and pour them together into a 

 vessel. It is usually preferable to have a bucketful or so of water in 

 the receptacle into which the solutions are to be poured, but this is 

 not essential. 



