84 THE GRAPE ROOT-WORM. 



arsenate of lead for spraying purposes and the sharper competition 

 among manufacturers to secure the trade have been the means of 

 considerably lowering its cost to the consumer and the matter of 

 price should no longer be a bar to its use. 



COMBINING INSECTICIDES WITH FUNGICIDES. 



Since the use of a fungicidal spray for grapevines is highly desirable 

 and frequently absolutely necessary to hold in check fungous dis- 

 eases such as mildew and black-rot, and since some of the applica- 

 tions for these fungous diseases and the insect pest may be made 

 at the same date, it has become customary to combine the two 

 treatments by adding poison in the form of arsenate of lead to Bor- 

 deaux mixture, the fungicide used against the fungous diseases. 



The formula recommended for this combined treatment is asfollows: 



Pounds. 



Copper sulphate (blue vitriol) 5 



Fresh stone lime 5 



Arsenate of lead 3 



Water 50 



When Paris green or arsenite of lime are the arsenicals used, 4 

 ounces of the former, or 1 quart of the latter prepared according to 

 Kedzie's formula, may be added to 50 gallons of Bordeaux mixture. 

 For reasons given above the use of arsenate of lead in preference to 

 either of these other arsenicals is strongly urged. We here include 

 detailed directions for making Bordeaux mixture which are given 

 by Mr. C. L. Shear, of the Bureau of Plant Industry, in Farmers' 

 Bulletin 284, treating of fungous diseases of the grape. 



PREPARATION OF BORDEAUX MIXTURE. 



Failure to secure satisfactory results from the use of Bordeaux 

 mixture is frequently due to lack of proper care and thoroughness in 

 its preparation, or to the use of poor material. All ready-made 

 preparations of Bordeaux mixture in the form of a paste or a dust 

 should be avoided, as the chemical constitutents do not properly 

 combine in these conditions. A definite chemical compound is desired, 

 and this can only be produced in proper form and condition by care- 

 fully following the directions given below: 



Stock solution. — In order to carry on the work with the greatest convenience and 

 economy, a considerable quantity of copper sulphate and of lime should be ready for 

 immediate use. The copper and the lime may be prepared and kept most conven- 

 iently in the following manner: 



Copper sulphate solution. — Take 100 pounds of copper sulphate (bluestone), place 

 it in a gunny sack, and suspend it in a 50-gallon barrel of water. Kerosene or whisky 

 barrels will be found very convenient. The copper sulphate will all dissolve in from 

 12 to 18 hours if suspended in a loosely-woven sack, but if it is thrown loose in the bot- 

 tom of the barrel it will take several days and considerable stirring to dissolve it. This 



