49 



unfolding that the attacks of these fnngi occur most commonly. I 

 have seen several thousand ti-ees affected on one estate within a few 

 weeks. Glceosporium is frequently the cause of the fall of the 

 young leaves before they are fully developed — an effect of not 

 uncommon occurrence. 



As far as tliese two fungi are alone concerned the attacks 

 are not dangerous. Dead twigs killed by the fungi are often found 

 but the disease spreads no further. The real danger lies in the 

 fact that their attacks afford opportunity for the entrance of 

 Botryodiplodia and for this reason affected bi'anches should be 

 removed and all diseased portions burned. 



More often than not, especially in flat lands, Botryodiplodia 

 makes its entrance after the attacks of these fungi and therefore 

 it is necessary that the utmost precautions should be taken to 

 prevent a serious local epidemic of die-back. 



Thread-Blight. 



The mycelial strands of this fungus appear like white threads 

 running along the small branches and twigs of affected trees 

 collecting and binding together leaves in bunches. Leaves are 

 frequently killed and sometimes small branches. The bunches of 

 dead leaves and leaf stalks found bound together by the threads 

 render the fungus conspicuous. 



Dead leaves or collections of leaves may be bi'oken off and 

 carried by wind or some other agency to other healthy trees where 

 the fungus may start developing again and so spread the disease. 

 Leaves of two trees may, so to speak, be sewn together by the 

 threads and this is another way of spreading the infection. 



Fortunately, the disease is easily treated by cutting away 

 affected parts and as generally only small branches are attacked the 

 loss occasioned is insignificant. 



On one plantation I found this fungus in fructification and sent 

 it to Kew for identification wliere Massee named it Cyphella hevese, 

 but this is a matter which required further evidence or confirmation 

 befoi^e we can be satisfied that the fungus belongs to this particular 

 genus. 



Phytophthora species. 



Here I come to the most important part of my paper. In 

 Ceylon, South India, Burma, Java and Sumatra a disease known as 

 canker and proved to be caused by PhytopJithora Faheri has been 

 known for several years. The disease was found in Ceylon in 1903. 

 In January last I heard that on a certain estate a disease had 

 appeared on the tapped surface. Through the courtesy of the 

 manager I was permitted to look round the estate and it was 

 obvious at once that the disease was extremely serious for in 500 

 acres of well-matured rubber tapping had ceased. I was not able to 



