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Pink Disease of Plantation Rubber 



base of the culture tubes. Similar experiments were performed at 

 the same time with Cojfea liberica as host. The following table sum- 

 marises the results on August 19th: 



Thus successful inoculations of both rubber and coffee were obtained 

 with pure culture material of the fungus. 



Kant experimentally demonstrated that Corticium salmonicolor does 

 not exhibit the phenomenon of specialised parasitism. Thus this 

 fungus occurring on one host is not limited in infective power to that 

 particular host or a few others, but can attack a wide circle of plants. 

 It passes readily under favourable conditions from one host to another. 

 Only in very wet weather does the fungus spread rapidly, as was 

 obvious in our field experiments. Relatively few of our inoculations 

 were successful and this we attribute to the difficulty of keeping them 

 moist during the spells of dry weather which intervened during the 

 progress of the experiments. 



Treatment. 



It must be pointed out in the first place that, exceptional cases apart, 

 spraying with fungicides is impracticable and to some extent also 

 useless. Spraying a rubber plantation with trees 30 to 60 feet high is 

 an entirely different proposition from spraying an orchard containing 

 trees only 20 feet or so high. There would have to be something in the 

 nature of a revolution in spraying methods to enable a mature rubber 

 plantation to be sprayed effectively so as to check Pink Disease. 

 Spraying experiments which we recently carried out with two modern 

 machines provided with extension rods show that the maximum height 

 for which they can be used under estate conditions is 25 to 30 feet, and 

 this height is only obtained with difficulty by coolie labour. Longer 

 extension rods have been tried, but the difficulties of manipulation 

 under estate conditions are so great that they cannot be used with 



