CLEAN CLEARING, PESTS AND DISEASES. 
By W. R. Shelton -Agar, 
(Manager, Kamuning Estate, Perak, F.M.8 . ) 
If I were asked to classify the various diseases and pests 
according to their relative activity in regard to rubber plant life, 
I should put disease into two classes — 
(1) “ Those that are fatal ” ; 
(2) “ Those that are amenable to treatment ” ; 
and pests into both, viz, : 
Fatal class (I). 
All root diseases — such as 
Fomes, Hymenochsete, Ustulina 
and Poria. 
Amenable class (II). 
Stem and bark diseases — such 
as pink disease, Dijplodia, thread 
blight and cankers. 
Pests — Termes gestroi and borers. 
1. do not include vermin, as most wild animals, so far as rubber 
is concerned, could be classed as such and measures to deal with 
them, as a rule, are easily attended to. 
As it will be impossible in a paper of this kind to deal 
individually with them all, I shall merely offer, for discussion 
categorically, four salient points : 
Prevention ; Incidence and 
Treatment ; Control. 
Prevention of Disease. 
So long as there is “ no cure ” for any fatal disease, obviously 
the next best thing is prevention. 
Now prevention in this case means eliminating causability, or, in 
other words, having reference to all the fatal diseases and pests 
of class one. 
The argument in favour of “ clean clearing ” is not mere theory, 
it has a practical side as well. Take those rubber estates that have 
been developed out of old tobacco, tapioca and lalang lands, they 
rarely give evidence of any appreciable trouble, and though we 
have these practical illustrations, timber clearing has never yet 
gained the whole-hearted support it merits. In some cases it is 
undoubtedly a matter of £ s, d., but in others it is not so. Some 
planters hold that by clearing timber much valuable humus matter 
is lost,” and also that “ no immunity exists from pests and disease so 
long as the roots and stumps of trees are allow ed to remain in the 
ground.” 
These are admittedly weighty views, and the arguments are 
correct up to a point. 
