48 1 



VII. — Native Trees Attacked. 



Among native trees T. gestroi appears mainly to attack 

 species of the genus Macaranga, which, it is significant to note, 

 belongs to the same natural order as Hevea brasiliensis. Jelutong 

 {Dyer a costulata) is also affected, but not to any serious extent, 

 and so are various species of Mango, both wild and cultivated. 



Grown under artificial conditions, tembusu (Fagraea fragrans) 

 has been damaged, especially in the neighbourhood of Seremban 

 and near Tampin. On one estate, where Grevillea robusta has 

 been planted as a shade tree, the ants have practically extermi- 

 nated it. Coconuts are also affected but not to anything like the 

 same extent as Para rubber. Rambong is but slightly attacked, 

 and when it is, generally survives, a result probably due in part 

 to its constitutional powers of resistance and in part to its habit 

 of growth. 



VIII. — Age of Para when Attacked. 



It is very rare for any material damage to be done before the 

 tree is 3J years old, but I can find no satisfactory explanation of 

 this undoubted fact. It may possibly be that Termes gestroi is 

 naturally so scarce and scattered that it takes an appreciable 

 time for a sufficient stock to accumulate, but more probably the 

 species cannot work without a minimum amount of shade, which 

 is not afforded until the age of 3 to 4 years is attained. x\ third 

 theory, to which a certain amount of plausibility attaches, is that 

 the nests of the ants, as with certain South African species, are 

 normally situated at a considerable depth beneath the surface, to 

 which the roots of the rubber do not extend until the age of about 

 four years, though this again is discounted by the situation of the 

 nests as actually found. 



IX. — Influence of Soil upon T. Gestroi. 



It has been demonstrated from returns sent in and from various 

 typical estates visited, that, other things being equal, the damage 

 caused by this pest varies more or less directly with the heaviness 

 of the soil, light sandy loams being almost unaffected, while heavy 

 clay soils have sometimes as many as 25 per cent, of the trees 

 attacked. As regards drainage it is impossible to lay down any 

 general rule. Swamp land is almost free from any species of 

 termite, but, on the other hand, where the natural water level lies 

 far beneath the surface termites can penetrate to a correspondingly 

 great depth, and speaking broadly it may be said that the hill 

 country estates in Negri Sembilan are more badly affected than 

 those of the flats in Selangor, though possibly other causes may 

 also have contributed to this. 



Taking all considerations into account, it has, I think been 

 fairly demonstrated that the land best suited to Para rubber is a 

 fairly stiff soil, capable of retaining a certain amount of moisture 

 during drought, which is provided with a thoroughly efficient 

 system of drainage. The slightly increased percentage of trees 



