362 
THE TROPICAL 
AGRICULTURIST. 
(Nov. 1, 189&. 
tivity is found to hava spread gradually and if this 
is again cut out as a rule the fungus i; killed. In 
all cases where this second ii'lempt or at any rate 
the tliird has been made to kill the fuiij^us by ex- 
posure and without success Uie best plan is to cut 
down and burn the tree leaving of course a sturap 
as far as possible for the production of " suckers." 
The question of growing "suckers" in cacio is an 
extremelj- interesting one. Apart from the question 
of the canker, but in regard to the canker more im- 
portant still. In ray experiments I inoculated the 
stems of 30 healthy trees and 26 of these acquired the 
canker, but in the case of '■ suckers '' out of ten 
" suckers" so treated 1 only procured the disease in 
one instance, Tlie infrequeiicy of canker on the 
suckers compared v/ith stem and branches even 
in badly diseased estates is most noteworthy ; 
and th's is a most important recommendation 
in support of the practice of leaving the suckers 
and not as is the usual practice cutting them out 
wherever thny appear. The whole qnestii'n is 
perhaps more for the experience of the planter to 
deal with, but my observation lead me to doubt 
the advisability of the hard and fast rule to re- 
move suckers from the tree without reg.ird to the 
respective requirements of each plant ; and in cases 
of estates where they were left, t'.ie health and 
cropping of the trees seem to me batter. So that 
when in addition to this we find that the suckers are 
less affected by the disease it still further points 
to the desirability of at any rate trying the plan 
of allowing trees to produce suckers. One is told 
that suckers tnkd a long time to produce fruit but 
from observations taken we find that fruit is borne 
on suckers very litlle more than a year old. In all 
cases where a tree is cut down to a stump it is well 
to put in a supply plant so that should the suckers 
not form or not produce a good tree, time will not 
be wasted. 
SVMMING UP. 
To sum up the measures which experiments have 
shown to be of value, 
1st. In all cases of cankered trcei to excise all 
diseased tissue, being careful to cut out all round 
beyond the discolouration. 
2nd. Burn all diseased parts so removed. 
The treatment by shaving only to be resorted to, 
^hen the entire removal of the diseased tissue would 
bo likely to prove fatal to a large number of 
trees. 
The best time for examining the trees is just after 
the rainy season when the stems of the trees are 
dry. It is very diflicult to detect any signs of the 
canker on the cortex, when the trees are wet during 
rains and the fungus wliich begins during the damp wea- 
ther has not had time to produce a noticeable patch. In 
All estates ther« should be an inspection, and in 
places where the disease is unknown, ic would bd ad- 
visable that an intelligent coolie should be sent torn 
estate where the canker exists in order to make him- 
self familiar with its appearance; two or three days 
With the canker cutting coolies on any good estate, 
would enable an average coolie to readily recognise 
it, and he would also lenrn the most workman-like 
methods of cutting out without doing more damage to 
the tree than is necessary. 
If any doubt is felt with regard to a dark spot on a 
tree, a slight scratch with a Icnife will reveal the bark 
below either healthy or discolored. 
There is another advantage attached to this cutting 
out of cankered spots which ihe planter will soon 
find out. The white borer originates in the great 
proportion of cases in the cankered places, the soft 
wet tissue there being more easily penetrated ; on an 
estate, therefore where cutting out the borers has 
bad to be carried out pretty fi-equently a great 
decrease will be found, when all the aiseased patches 
are I'emoved, and the same coolies who deal with 
the canker can easily add the cutting out of borers to 
their duties. 
Since beginning to write this Report I have had 
brought to my notice a canker on the thorny Bois 
r-ft tree extensively used loi shade \ 
cacao estates — (Erythrina nrnbrosa) — a canker which 
on ex iminatioii, proved to be the cacao canker, and 
in^^eed experiment illy proved by inducing the canker 
in cacao trees with inocnlitioiis of diseased ti-isue 
and spores from the Erythrina. There is no doubt- 
considering the infrcquency of this disease on the 
Bois, even in estates where the majority 
of the cacao trees are cankered that it has 
come from the cacao to the Erythrma, and 
not vire veisa, but it bfliovea planters to look 
to theii shade trees, and to treat them eurgically as 
well as their cacao trees whenever they notice any 
signs in them suspected to be canker. 
Though in the first instance these investigations 
were directed to the canker disease and its effects 
another disease attractid my notice, and is of great 
importance to cacio growers us it affects the pods 
and consequently damages the crop in some cases to 
a very large extent. 
rOD DISEASE. 
This pod disease is very easily distinguished from 
the other enemies affecting the pods, viz., Helo- 
peltis-borers, and squirrels iVc It causes a browning of 
the hufck, which almost invariably begins either at 
the stalk or point of the po 1 and u<>t in the niiddlo, 
and is marked by a definite line. (Pi{,'. .'>). On 
cutting the pod open, it is found not to be super- 
ficial like the brown, or black marks caused by Helo- 
pellis, but to spread through the entire thickness 
of the husk, and if it has been going on for a few 
days iiffectiug, and di.scolouring the seeds also. This 
disaai^e is caused by the presence of the mycelium of 
a funfjus in the soft ti^^sues of the fruit, the fun- 
gus belongs to the same group as the Potato disease. 
It produces its fruits of reproductive bodies in the 
furrows of the pod where Ihoy can be seen as a white 
mould. On examination microscopically tliey will be 
ionnd to consist of spherical or egg-shaped babies con- 
taining round spores. 
Pods attacked by this fungus are completely des- 
troyed in about ten days. An important fact to re. 
member is that once the pod is atlacked by this 
fungus the seeds never increase in size all the nutri- 
tion being taken up by the quick growing mycelium. 
It is, therefore, of no use to keep any diseased pods on 
a tree as no r pening or enlargement of the seeds 
takes place— only increase and spread of the fungus. 
Very strict meivsures fhould be taken on estates where 
this disease exists, and all pods affected should be 
taken off directly any sign of the disease is noticed 
and huiiit. By this means the number of spores is 
reduced, and if carried out for some time the evil 
should be lessened to a great extent. Of course as in 
the canker the wet season is the time when this fun- 
gus flourishes in a dry season it is not often met with. 
Bi'fore concluding this llcport I must refer to the 
great assistance I have received in carrying out these 
investigations without which it would have been 
almost impossible to hare gained any of the know- 
ledge which is recorded here. The information 
afforded by planters has been most valuable. Of the 
greatest use are records which are nsnally kept — the 
rainfall; the crops each month; the deaths dne to 
disease— ravages of insect enemies, &c., &c., all of 
which lead to an increased knowledge in helping 
cacao to a healthy life. Agricnlturalists at home might 
well take a leaf out of the Ceylon planters' book in 
regard to these matters. 
My thanks are especially due to those planters 
whose estates I visited and who in all cases added 
to the pleasure of my visits by their hospitality and 
kindness. 
Th-se investigations have at times presented tome 
disappointing difficulties, but have always been of the 
greatest interest to me, and with so lauch still to learn 
of the cultivation of cacao, and the battle with its 
various enemies, fungi, insects, &c., I leave my obser- 
vations and experiments with regret ; but still with 
the hope that Ceylon cacao planters will continue to 
gain knowledge as to their cultivation, so that they 
may grow cacao to greater perfection and with in. 
creased profit. J, B, CARKUXHERS, 
