DISEASES OF SHADE AXD FOREST TREES. 121 



advantage. Potassium sulphide solution is a very useful 

 remedy where it is desirable to protect ornamentals against 

 powdery mildews and other superficial fungi. 



FUNGICIDES. 



Bordeaux Mixture. 



Copper sulphate 2 to 5 pounds 



Quick lime 3 to 6 pounds 



Water 50 gallons 



This is one of the oldest and most reliable fungicides 

 known. The lime is to prevent certain injuries which might 

 otherwise arise from the use of copper sulphate and the 

 amount should always be slightly in excess of the amount 

 of the copper sulphate. The copper sulphate is dissolved in 

 a small quantity of w r ater by suspending the crystals in a bag 

 at the surface. The lime is slacked in a small quantity of 

 water. Each mixture is then diluted to 25 gallons and the 

 two are poured together. The copper sulphate may be dis- 

 solved, and the lime slacked, and the two kept as stock for 

 dilution and use as needed but the mixture will not keep 

 after being poured together. The strength of Bordeaux mix- 

 ture varies with the character of the foliage of the plants to 

 bo treated, since the foliage of many tender plants will be 

 injured by it. 



Copper Sulphate. 



One pound of copper sulphate dissolved in 25 gallons of 

 water makes an excellent winter spray but cannot be used on 



plants when in foliage. 



Lime-Sulphur. 



This mixture has come into general use as a winter spray 

 and has largely superseded copper sulphate since it serves as 

 Wh a fungicide and an insecticide. The commercial prod- 



