EXPERIMENT STATION BULLETINS. 469 



FUNGICIDES. 



As noted above the use of the fungicides is to cover the plants and to 

 destroy the spores of fungi which fall upon them. For this purpose 

 Bordeaux mixture is most valuable. 



BORDEAUX MIXTURE. 



Copper sulphate (granulated) 4 pounds 



Lime (fresh) 4 " 



Water 40 gallons 



The above is known as the 'one to ten' formula and may be slightly 

 modified without destroying its efficiency. When preparing Bordeaux 

 mixture it is advisable to first make a stock solution that can be mixed 

 and used as desired. Take twenty-five pounds of copper sulphate and 

 suspend it in an old basket in twenty-five gallons of water. In a few hours 

 it will dissolve. In a box slake twenty-five or more pounds of lime. (If it 

 will be used within a week it will be well to slake the entire barrel.) Add 

 water only as fast as it is taken up by the lime, but take care that it does 

 not become dry and burn. In slaking a few pounds it is well to start it 

 with hot water. When desired for use, for forty gallons take four gallons 

 of the copper sulphate solution, after giving it a thorough stirring; place 

 in a barrel and dilute to twenty gallons'. Then take as much of the slaked 

 lime as would be made from four pounds when unslaked, dilute this to 

 twenty gallons and add to the diluted solution of copper sulphate. Pour 

 together slowly and stir rapidly while doing so, that they may form a per- 

 fect mixture. The dilution might be made after the ingredients are mixed, 

 but it soon settles to the bottom, and does not give as satisfactory results. 



When fresh (unairslaked) lime is used, and the right proportions have 

 been added, there will be no danger of injury to the foliage, but that there 

 may be no mistake from having too small an amount of lime, it will be 

 well to test the mixture in some way. This can be done by adding a drop 

 or two of ferro-cyanide of potassium, and if it changes to a reddish choco- 

 late color it indicates that more lime is required. When no change in 

 color is produced it indicates that the amount of lime is sufficient, but a 

 considerable excess will do no harm. Another test is to dip a knife blade 

 into the mixture and if on drying a film of copper is deposited the need 

 of more lime is shown. When good lime is properly slaked there will 

 be no sediment, but it is always well to stir up the diluted lime water 

 and pass through a brnss strainer. The lint from burlap bags, which 

 are often used, is likely to give trouble by clogging the nozzle or pump. 



COPPER SULPHATE SOLUTION. 



For use upon trees while dormant, the strong solution, 



Copper sulphate 1 pound 



Water 15 gallons 



may be used, but for use after the fruit is ripening a diluted formula, 



