58 PARA RUBBER. 



this disease appear on a plantation, its spread may be checked 

 by digging a trench about a foot deep around each affected tree, 

 throwing all soil taken from the trench within the circle and 

 dusting it with powdered sulphur. 



Trees destroyed by the fungus ought not to be allowed to lie 

 rotting on the ground, but should be burned, as they form hot- 

 beds for the propagation and dissemination of the disease. 



In the Malay States also a fungoid root parasite has been 

 found attacking the roots of some trees. 



Mr Stanley Arden says : * " There has been some discussion 

 as to whether the loss of trees is attributable to this fungus or to 

 the ravages of the white ants, or to both, but in the large majority 

 of trees I have examined, neither one nor the other could be 

 said to have killed the tree. Had the trees been killed by the 

 fungus there would doubtless have been some indication of its 

 presence some time previous to the tree falling over ; but, as 

 already stated, at the time of falling the trees generally appeared 

 to be in a robust condition, and I incline to the belief that the 

 fungus had prepared the way for the ants, which by eating away 

 the heart of the trunk had caused the trees to fall simply for 

 want of support." 



Leaf Diseases. According to Fetch, "the commonest leaf 

 fungus of Hevea is that of ' Grey Blight,' Pestalozzia guepini, 

 Desm. ; this is comparatively harmless on leaves but kills the 

 seedling when it attacks the stem at the collar ; the diseased 

 patch usually takes the form of a white ring surrounding the 

 stem, bordered by a purple-brown line." 



It is important to remember that this is one of the most 

 destructive parasitic fungi which attack the tea plant both in 

 India and Ceylon. Massee states : " As the mycelium is not 

 perennial in the tea plant, if all affected leaves were collected 

 with the amount of care and intelligence exercised in collecting 

 sound leaves, and burned at once after being collected, the 

 disease would soon be stamped out." 



Another fungus which attacks Hevea leaves is Helmintho- 

 sporium hevea, but though abundant is of less importance than 

 the previously mentioned species. This causes small round 

 transparent spots on the leaves ; these spots are usually 



* Report on Hevea brasiliensis in the Malay Peninsula. 



