24 GARDEN FOES. 



CHAPTER IV. 



FUNGICIDE FORMULi«. 



The follo\\ing are excellent formuLie for the preparation 

 of effective fungicides : 



20. Bordeaux Mixture — One of the most important 

 of all the fungicides, and the most widely used, is Bor- 

 deaux Mixture: 



Copper sulphate 21b. 



Fresh-burned lime 2 1b, 



Water lOgal. 



The copper sulphate is dissolved in about half the water 

 in a wooden vessel, large enough to contain the whole; 

 and the lime is dissolved in another smaller one. When 

 the copper sulphate is dissolved and the lime has 

 settled after being slaked and well stirred up in the water, 

 the clear lime water is added to the copper sulphate until 

 the liquid, on allowing the blue precipitate which is 

 formed to settle, will not turn blue litmus paper red, or 

 will give no brown discoloration on the addition of 10 

 per cent, solution of potassium ferrocyanide. A useful 

 v/ay of having Bordeaux mixtin^e ready at shoit notice is 

 to keep a stock solution of copper sulphate of 31b. to the 

 gallon of water. This is what is known as a saturated 

 solution, and as long as a greater amount of copper sul- 

 phate than this 31b. to the gallon is kept hanging in the 

 water the solution will remain tlie same strength at all 

 ordinary temperatures. If any of the water evaporates 

 crystals of copper sulphate will be deposited until the 

 liquid gets to its right strength, and if more water is 

 added more of the salt will be dissolved to restore the 



ftOfERTY LlBRAWr 



