Oct. I, 1897.] 
THE TROPICAL AGRICULTURIST. 
273 
10. In most other cacao-growing countries the 
old red or Griollo varieties have been or are being 
replaced by the hardier Forastero, and it seems 
likely that this vyill be found necessary in Ceylon. 
The latter variety yields a less valuable crop, but 
its vigorous growth and larger yield may prove com- 
pensating advantages, 
11. Experiments to test various modes of combat- 
ing the disease are in progress upon an estate in 
Matale, but no results can be anticipated till after 
the break of the north-east monsoon. 
12. The chief work of a specialist if obtained would 
be to investigate the life history of the organism to 
which the disease is due. Once provided with such 
knowledge we should be in a better position to in- 
telligently apply remedial measures. The actual 
remedies or preventives usually applied in the case 
of fungus diseases are already well known to skilled 
agriculturists, but their success commonly depends 
upon their being applied at a particular time in 
the life of the parasite causing the disease. 
13. We are of opinion that the bulk of the old 
red variety in most districts of Ceylon is doomed 
to gradual extermination as a profitable crop, and 
that therefore it would be better to continue to re- 
place it with the hardier varieties than to expend 
much time, labour, and money in endeavour- 
ing to retain it. In favoui’ed spots the more delicate 
variety may survive uninjured for many years. — 
John C. Willis, Director, Eoyal Botanic Gardens; 
E. Ernest Green, Hon. Government Entomologist. 
Peradeniya, July 27, 1897. 
SUGGESTIONS FOB TREATMENT OF TREES ALREADY 
AFFECTED, AND FOR PREVENTION OF FURTHER 
SPREAD OF DISEASE. 
Diseases in plants are closely similar in cause, in 
action, and often even in nature, to those in 
animals. They are as a rule only serious when the 
organism is already weakened in some way. The old 
idea that a disease was always to be cured by ad- 
ministration of some definite remedy or drug is now 
dying out even in popular repute, and it is beginning 
to be more fully understood that the proper mode of 
treatment is to assist nature in throwing off the 
disease by placing the patient in such conditions of 
food, rest, &c., as will best prevent further weakening 
and tend to bring up the general health and strength. 
The use of drugs, &c., usually plays but a secondary 
part in the treatment. For the successful application 
of such treatments a thorough knowledge of the 
general constitution and previous history of the patient 
is of the utmost service. Hence comes the well-known 
' fact that an intelligent family physician is often 
able to treat a patient whom he has long known 
i much better than any specialist. Even when the 
family physician himself has been at fault and 
I has had to have recourse to a specialist, the 
! remedies suggested by the latter are often best 
; applied by the former. The same is true in the case 
in hand. Whilst remedies and treatments may be 
suggested by scientific men, it is for the individual 
' planter to decide for his own estate their application. 
' He is, or should be, best able to decide which, if 
any, of the suggested causes is the one to which the 
i! weakening of his trees is due, and which, if any, of 
! the remedial measures should be applied. 
I In paragraph 9 of our report we have called at- 
tention to some common causes of weakening of 
(' the trees. 
J The disease seems most often to have appeared first 
1 in very damp shady places. Drainage of the soil and very 
j' gradual reduction of shade may help here. It should 
I however be remembered that reduction of shade in- 
! creases the yield, and if this be allowed it will equally 
[weaken the trees. 
The disease is constantly found round holes in the 
bark, where water lodges, whether made by boring 
insects, by cutting the stem to remove borers or by 
removal of suckers. When wounds are made they 
should be covered with tar, tar and coconut oil mixed 
in equal quantities, tree wax, or other waterproof 
substance, It is however of little use applying these 
things at times when the sap is running up in large 
quantity (so that the stem bleeds when cut), for they 
will not then adhere properly. 
No more injury than is unavoidable should be caused 
in removing borers. Many trees that we have seen 
have been so hacked that it is a wonder how they have 
survived. Hacking the bark and pruning are two 
totally different operations, and while the latter may be 
beneficial the former in itself is not so, though it 
may be necessary in the removal of other causes of 
damage. 
When only a few spots of disease appear among vigo- 
rous trees, it will probably be found sufficient to out 
out the diseased part completely and cover the wound 
as directed above. 
When a stem is really badly diseased it should be 
cut down at once, the cut being made below the lowest 
diseased parts. Suckers will often spring from points 
below the lowest diseased portions and form healthy 
stems. 
When, however, a tree is dying away it should at 
once be entirely removed and its place supplied by 
R new plant. 
All diseased parts, stems, or trees, whether dying 
or dead, should be at once burnt. 
In areas where the disease is very marked the 
supplies put in should never be of the old red variety, 
but of Foreafero or other hardy kinds. 
In areas where the disease is really verj' bad, 
so that moat of the trees are dying, it 
would be better not to plant the land in cacao, 
if possiblCj till a few years have elapsed, 
but to put in some other crop for a time. Rotation of 
crops is one of the chief preventives against disease 
known to agriculturists.' 
Great care should be taken in selecting seed for 
sowing. Only seed of perfectly healthy trees growing 
in districts free of the disease should be used, and it 
would be better to obtain seed from abroad as faras 
possible. 
If the supplying with Forastero be done gra- 
dually so that the trees of this variety remain 
mixed with trees of the old red kind, the pods and 
seeds produced on the former will usually be found 
to show more or less of the Criollo character 
in colour, breaks, &c. This is due to the Criollo 
flowers being carried to the flowers of the Forastero 
trees by insects, &c. 
INFORMATION DESIRED. 
We shall be grateful to planters of cacao for any 
information relating to the disease ; its prevalence, 
the time of its appearance, whether it attacks young 
trees or Forestero trees ; its probable causes ; any re- 
medial measures tried, and their results, and so on. In 
making use of such information no names or places 
will be mentioned without special permission. 
.John 0. Willis, Director, Royal Botanic Gardens. 
E. Ernest Green, Hon. Government Entomologist. 
THE ROYAL BOTANIC GARDENS’ 
CIRCULAR IN RE-GAGKO. 
Sept. 9. 
Dear Sir, — It is strange that in the first cir- 
cular from the experts on the subject of cacao 
canker (so-called) no attention has been drawn 
to the beneficial results of using coral-lime and 
wood-ash. For years soils have been manured 
with cattle bulk, compost, bone dust, and bone 
meal, castor, superphosphates, guanos, cotton- 
seed and coconut jioonac, and perhaps a little 
niti ate soda and sulphate ammonia ; but in very 
few instances, if in any, has an adequate quantity 
of lime been applied. It would be interesting to 
know what amount of lime has been used the 
last ten years; but it is pretty cei t.ain the quan- 
tity per acre would work out absurdly low. A 
good proportion of cacao lands li.as been formerly 
cultivated in coflee, and we m.ay fairly assume 
that in coffee days there was the same failure in 
