Nj 6. DEPARTMENT OF AGRICULTURE. 751 



Tlie feLandiard formula for Bordeaux mixture is: 



Copper sulfate (pounds), 6 



Lime (jjounds), 4 



Water (gallons), 45 



"Potatoes will require from two to six barrels of the mixture per 

 acre according to the size of the vines. In case a large area is to 

 be sprayed it maj be well to make up a stock solution of copper sul- 

 fate. The following directions for making up the solution may be 

 found helpful. Into a barrel containing forty gallons of water sus- 

 pend in a bag or gunny sack forty pounds of copper sulfate or blue 

 vitriol. It is important that this be suspended near tihe surface as 

 the solution has a greater specihc gravity than water. If it should 

 be put in the bottom of the barrel a saturated solution would soon be 

 formed there, when no more of the copper would be dissolved. If 

 the barrel be covered tightly this stock solution will keep for an in- 

 definite length of time. 



"The lime used should be fresh burned, caustic and not air-slaked. 

 The most convenient receptacle in which to slake the lime is a some- 

 what shallow, long, water-tight box. To make up, say four barrels 

 of the Bordeaux mixture, put into this box sixteen pounds of lime 

 and add sullicient water to thoroughly slake. The lime should be 

 kept well stirred during slaking that the water may come in contact 

 with all parts. If it is desired to keep the lime for some days after 

 slaking, it may be simi)ly covered over with water so that the air will 

 be excluded. When it is desired to use it, stir thoroughly and put 

 one-fourth the contents of the box into a keg or other receptacle and 

 dilute with twenty gallons of water. If more than four barrels of 

 Bordeaux mixture are likely to be wanted, two slaking boxes would 

 better be provided so that the lime will be ready for use when re- 

 quired. 



"Into the barrel from which it is to be pumped, put six gallons of 

 the contents of the barrel containing the dissolved copper sulfate. 

 It seems hardly necessary to state that before doing this the copper 

 sulfate solution should be thoroughly stirred. Fill the spray barrel 

 half full of water and add the lime which has been diluted with 

 twenty gallons of w^ater. All of this material should be run through 

 a sieve or strainer so that no sediment will clog the action of the 

 pump. 



"If Paris green is to be used to kill the potato 'bugs' put it in the 

 mixture at this time, four ounces if the grubs are small, six ounces if 

 they are half grow^n. A paste should be made of the Paris green by 

 mixing it with a small amount of water before jjutting it in the spray 

 barrel. Fill the barrel with water and the Bordeaux mixture is 

 ready for use to protect potatoes from the flea-beetles, the blight and 



