^ MONTHLY. [>o 
XXI. 
COLOMBO, JANUA-RY 1st, 1902. 
No 7. 
CACAO CANKER IN CEYLON. 
History op the Disease, 
T is difficult to arrive at the exact 
date of the appearance of cacao 
canker in Ceylon : it had most 
probably being growing on 
cacao for a long period before 
it was noticed by planters. In 
1896 it was generally noticed, 
and various theories pnt forward 
as to its nature, some favouring 
the view that it was caused by au insect, others that 
the methods of cultivation were at fault. 
We may safely assume with our knowledge of the 
rate of growth of the organism causing the canker 
that it had been present in cacao trees at least five 
years previous to 1896, when in the public press and 
at planters' meetings the existence of the evil was 
recognized. The number of trees affected and the 
wide area over which the canker existed in 1398^ 
■when the investigation of its nature and life-history 
commenced, suppoits the presumption that cacao 
canker began in Ceylon not less than ten or twelve 
years ago. unhappily the disease was until 1898 
only treated in various empiric ways, without 
deflQite knowledge of the nature of the eveil. It 
was said to bo a fungus atticking the root, to 
especially attack weak trees, and to be a conse- 
quence of the attacks of boring and other insects, 
and from these premises various suggestions for the 
prevention of further spread of the disease were 
formulated. This has been almost invariably up to 
the present time the history of diseases of cultivated 
plants, and the experienca has been dearly bought 
that in plant life, as in human sanitation, sporadic 
diseases should be carefully investigated as soon as 
possible, and when their nature is discovered prompt 
m3a;iires taken to prevent thetn becoming epidemio. 
In 1898 I began an investigation into the causea 
of the disease, spending a year in observing the 
life-history of the fungus causing the mischief, and 
also in visiting and examining more than forty 
cacao estates in different district.^ of the Island 
and at various elevations (from 100 to 4,000 ft ). 
The results of this investigation were published in 
three reports by the Ceylon Planters' Association, 
and an abbreviated account, with rules for dealing 
with the canker, was printed in Singhalese and 
Tamil and circulated by the Government. 
The amount of damage done before any steps 
were taken to combat the evil is hard to estimate, 
but a most serious loss in crop was caused by the 
canker and a still more serious loss of trees ; some 
estates, for reasons which may perhaps be under- 
stood by the following account, were free, or almost 
so, from the disease, while others were entirely, or 
in great part, wiped out. 
Hi,d the organism causing the disease invaded 
the root — as it was erroneously supposed to do — 
as well as the stem of the cacao trees, the loss 
would have been more disastrous. When the stem 
was cut down suckers were produced from the 
stump and grew vigorously, without disease, produc- 
ing fruit, in some cases when only a year old, in 
addition, new plants supplied grew healthily b side 
the stumps of the old cankered trees, and these 
circumstances retrieved a great deal of the loss on 
many estates. 
On some estates the methods laid down for com- 
bating the spread of the disease have been most 
carefully carried out, on some others partial trials 
Cwhich, as a rule, are a mere waste of money) 
have been made, but in a large number of cases, 
notably native holdings, no measures have beeu 
taken to decrease the ravages of the diseevse. 
