Diseases of Fruit caused by Fungi 49 



cannot be; therefore I advise that, in the case of a disease, promptitude, 

 combined with the removal of infected plants from the neighbourhood of 

 healthy ones of the same kind, whenever practicable, will go far towards 

 preventing the outbreak of an epidemic. [G. M.] 



2. FUNGICIDES AND SPRAYING 



The term fungicide is given to various substances used, in solution 

 or in the form of a powder, for the purpose of killing fungi that are 

 injurious to cultivated plants. Unfortunately the idea of a fungicide 

 for the purpose of preventing plant diseases has in some instances been 

 taken up by parties who, lacking the necessary knowledge, have neverthe- 

 less attempted to palm off on the unsuspecting purchaser some quackery, 

 in many instances surpassing, if possible, the nostrums meted out by 

 certain parties as an antidote to all the ills that human beings ever 

 have suffered or ever will suffer from. 



From amongst the many fungicides known, Bordeaux mixture and 

 self-boiled lime-sulphur mixture are undoubtedly the best, and will meet 

 all requirements. 



Bordeaux Mixture. This fungicide consists of a mixture of sulphate 

 of copper (bluestone), quicklime, and water in the following proportions: 



Sulphate of copper ... ... ... 1 6 Ib. 



Quicklime ... ... ... ... 11 



Water 100 gall. 



Place the sulphate of copper in a coarse sack, and hang it just below the 

 surface of a few gallons of water in a cask until melted. In another 

 cask slake the lime gradually until it is reduced to a creamy consistency. 

 When both are thoroughly dissolved, each should be made up to 50 gall, 

 with water. Then pour the milk of lime and the solution of sulphate of 

 copper slowly into one vessel, and stir the whole thoroughly for five 

 minutes. 



For determining whether the mixture is safe to use, the usual test 

 is to place the blade of a knife in the solution for one minute. If the 

 blade remains unchanged, the solution is safe to use; but if the blade 

 becomes coated with copper, more milk of lime should be added. A more 

 certain test for the presence of free copper in the mixture is to put a 

 few drops of a solution of potassium ferrocyanide, along with some water, 

 into a white saucer, and to drop into this some of the clear Bordeaux 

 mixture. If the liquid becomes red or brown it shows that there is 

 copper in solution; whereas if there is no change of colour, the mixture 

 is safe to use. The addition of lime, as before, corrects the mixture. 



The preparation of Bordeaux mixture is given because it is very 

 important to remember that the home-made material is much superior 

 to any of the commercial mixtures on sale. It must also be borne in 



Vol. IH. 34 



