i 9 4 RUBBER AND 



been severely tapped, especially where the pricker had 

 been employed. The appearance of the nodules is 

 therefore apparently facilitated by anything which tends 

 to weaken the vitality of the trees. 



The outbreak in question occurred in the spring of 

 1911. At this time a marked difference in the severity 

 of the epidemic was observed on two similar plots of 

 Hevea trees at Peradeniya, each one acre in extent. On 

 plot A upwards of 60 per cent, of the trees were affected, 

 and on plot B only about 10 per cent. Plot A had 

 received during the two preceding years applications of 

 a concentrated mixture containing 1 50 Ibs. of sulphate 

 of ammonia, 100 Ibs. concentrated superphosphate and 

 100 Ibs. sulphate of potash. Plot B was un manured. 

 During the twelve months immediately preceding the 

 outbreak, plot A had been tapped by paring and 

 pricking with the spur-shaped pricker, whilst the trees 

 on plot B were pared only on a similar system. It 

 seems natural to associate the larger proportion of 

 nodular outgrowths on plot A rather with the pricking 

 than with the manuring, but it is apparent that the 

 whole subject requires further study. 



General Sanitation. 



In a well lighted plantation which is kept clear 

 of decaying stumps and branches, fungus diseases are 

 not likely to make their appearance except sporadically. 

 Close planting and the presence of intercrops produce 

 conditions favourable for the introduction and spread of 



