Insect Pests and Fungoid Diseases. 405 



FUNGICIDES. 



BORDEAUX MIXTURE. This is the most generally useful and effec- 

 tive fungicide. On some plants, and especially in continuously damp 

 weather, it may injure the foliage, and it may also be objectionable on 

 ripening fruit, as it leaves a visible stain. In the latter case cupram may 

 be used as a substitute. A really fine misty spray, backed with plenty of 

 pressure in the machine, is necessary to get the best results from this 

 mixture. It should be used within twenty-four hours of mixing ; when left 

 longer than this it is difficult to keep the ingredients in suspension. The 

 same tendency to settle out quickly is found in the ready-prepared powdered 

 forms of Bordeaux mixture sold under various names. A ready-made 

 mixture is handier to use than a home-made one, and it is probably safer 

 in inexperienced hands, and the Woburn Bordeaux paste is probably the 

 best ready-made form. 



To make ordinary Bordeaux mixture take 



Copper Sulphate (98 %), 4 Ibs. 

 Quicklime (in lumps), 4 Ibs. 

 Water, 50 gallons. 



If the sulphate is obtained from a reliable source the powdered form is 

 best, as it will then dissolve in water much more quickly than when in 

 crystals. Tie it in a coarse bag and suspend in half the quantity of water 

 in a wooden vessel (a vessel of iron or tin must not be used). Put the lime 

 in a pail with a small quantity of water. If it is fresh and in good condition 

 it will heat up well and crumble to a fine powder in about fifteen minutes. 

 Stir up the lime in the remainder of the water and run it through a medium 

 strainer, then pour gradually into the copper sulphate solution, stirring well 

 all the time. The mixture should be allowed to settle and the clear liquid 

 tested for free copper. To do this, put a little in a white saucer and add a 

 few drops of a 10 % solution of potassium ferrocyanide. If a brown pre- 

 cipitate forms add more lime to the mixture and test again. Before using 

 pass through a strainer with 35 to 40 holes to the linear inch. 



The following modification of an Italian formula is given by Mr. S. U. 

 Pickering, of Woburn, and has given excellent results with us : 

 Copper Sulphate (98 %), 2lbs. 

 Lime Water, 34 gallons. 

 Water to make 40 gallons 



Dissolve the sulphate in 2 gallons of soft water. Slack 2lbs. good quick- 

 lime, as directed above, and put the powder in a tub with about 60 gallons 

 of water ; stir once or twice and allow it to settle. Add 34 gallons of the 

 clear liquid to the copper sulphate solution, stirring well ; test as in the 

 first formula, and add more lime-water if necessary, 



It is claimed for this mixture with lime-water that it is more economical 

 than the ordinary mixture, is more quickly effective, is less liable to be 

 knocked or washed from the foliage, and is more easily applied, 



