54 PARA RUBBER. 



FUNGICIDES. 



Fungicides are plant poisons diluted to such an extent that 

 they are harmless against the thick-walled tissues of the host 

 plants but sufficiently strong to destroy the tender fungus tissues. 



The following fungicides have been selected from those 

 which have given the best results in the treatment of fungus 

 pests : 



Bordeaux Mixture. This is usually prepared by dissolving 

 copper sulphate in water and mixing this with lime water. The 

 following proportions and mode of preparation have given 

 generally satisfactory results : Weigh 2 Ibs. of copper sulphate, 

 and immerse this, tied up in a piece of sacking, in 8 gallons of 

 water. Slake ii Ib. of lime, add water in small quantities and 

 stir until a perfectly smooth paste is obtained, then add 

 sufficient water to make 8 gallons of lime water. This should 

 be thoroughly stirred and when cool slowly mixed with the 

 water in which the copper sulphate has been dissolved. Professor 

 Pickering has recently suggested the following proportions as 

 being more economical and quite as effective, viz., 2 Ibs. of 

 copper sulphate and 27 gallons of clear, saturated lime water. 

 We have not experimented with this mixture, and should advise 

 tests being made before applying it on a large scale. 



Potassium Sulphide Solution. Mix potassium sulphide, or 

 what is better known as " liver of sulphur," in the proportion of 

 \ Ib. to a gallon of hot water, then add sufficient water to make 

 9 gallons of the solution. 



Ammonia and Copper Carbonate Mixture. Mix \ Ib. of 

 carbonate of copper with \\ Ib. of carbonate of ammonia, and 

 thoroughly dissolve in hot water; then add sufficient water to 

 make 64 gallons of solution. 



Each of these mixtures may be applied with sprays fitted 

 with nozzles which distribute the liquid in the form of a fine 

 mist. 



Hevea Canker. The fungus which is responsible for the 

 disease known as " Hevea Canker " belongs to the genus Nectria 

 and is therefore nearly allied to that which produces " Cocoa 

 Canker." Carruthers, in his report upon his investigations of 

 the first mentioned disease, states * that he found it on almost 



* Circulars of the Royal Botanic Gardens, Ceylon, vol. ii., No. 29, 1905. 



