F. T. Brooks and A. Sharples 75 



showed any trace of the fungus and it appeared that the fungus was 

 dying or was hibernating in the bark. 



The inoculations were examined from time to time, but the fungus 

 made no further progress. This result may be attributed to the 

 dry weather which followed the moist spell ending on March 16th. 

 A similar result is often observed on estates, for branches of rubber 

 trees may recover from an attack of Pink Disease if a long spell of 

 dry weather intervenes. 



Similar experiments were carried out in the field at the same time 

 on Coffea liberica, Cinchona succirubra, Cinchona ledgeriana, and Cinna- 

 momum camphora, six inoculations being made in each host, three being 

 in wounds and three being on unwounded surfaces. Only one successful 

 inoculation was obtained and that on Coffea liberica where the cobweb- 

 like form of mycelium appeared over the wound in which the fungus 

 had been inserted. 



The results indicate that these hosts are attacked less vigorously 

 than is Hevea brasiliensis. These experiments indicate the possibility 

 that small portions of the sterile incrustation may disseminate the 

 disease. These easily break away and are blown about by the wind. 

 Under favourable conditions the mycelium may develop and give rise 

 to a new infection. 



Inoculations were subsequently commenced in the laboratory with 

 pure cultures of the fungus. Rubber seedlings and plants of Gardenia sp. 

 and Cinchona succirubra were inoculated either by tying wood blocks 

 used in growing pure cultures upon the stem, or by placing pieces of 

 the mixture of mycelium and cotton wool from the base of tubes in 

 wounds in the stem or in contact with the stem. Six inoculations of 

 rubber seedlings and of Cinchona and three inoculations of Gardenia 

 were made on July 10th, but by August 19th no success had been 

 obtained. In these experiments the plants were kept under bell jars. 

 The inoculations on Gardenia and Cinchona were overgrown with moulds 

 within a week. In several inoculated rubber seedlings, however, the 

 fungus appeared to grow strongly at first, but it soon weakened, and on 

 August 19th the host plants were quite healthy. The experiments 

 indicate that Pink Disease is not likely to attack very young plants of 

 Para rubber. 



Inoculations of rubber trees with pure cultures were also carried 

 out in the field, trees standing in an overgrown nursery being used for 

 this purpose. Fairly large branches of the outside trees were inoculated 

 on July 14th with the mixture of mycelium and cotton wool from the 



