Jan. r, 1898.] 
THE TROPICAL AGRICULTURIST. 
499 
ters “ Black” cacao. The fruit is subject to it i 
many cacao growing countries. The disease as far 
as we can ascertain is, although present, not very 
common in this colony. The external signs of an 
attack of the disease consist of the following : first 
a minute brownish black spot or spots forms on the 
outside of the pod as a rule towards the lower part 
of it but freqnently in the middle and occasionally 
near or at the top. In the majority of cases this 
first appears at the time when the cacao fruit has 
attained a considerable size and is approaching its 
period of ripening. The spot or spots rapidly in- 
crease in size producing large patches of a blackish 
brown colour which appear over the lower part of 
the pod, in the middle of it or all over the top and 
if the fruit is allowed to remain on the tree it 
rapidly becomes black all over and partially rotten. 
On opening an affected pod when the disease has 
somewhat advanced it is found that the pulp sur- 
rounding the beans in the immediate vicinity of 
the blackened part of the husk is slightly disco- 
loured, whilst in the more advanced stages of the 
attack the whole of the pulp becomes browniih yellow 
in colour and evolves a characteristic sour and 
somewhat offensive odour. Later it quite dries up, 
leaving the beans bare. 
Where a diseased pod is in contact with a healthy 
one the disease in many cases extends to the healthy 
one. Microscopical examinations of the diseased 
fruit show that the blackened exterior is occupied 
by the mycelium of a fungus which gradually makes 
its way from the husk into the pulp surrounding the 
beans and finally into the beaus themselves. The 
blackened husks if kept for a short time becomes 
covered with a light coloured incrustation consisting 
of vast numbers of the spores of the fungus. We 
have found that these spores when brought into 
contact with healthy fruit give rise to the same 
disease. We have been informed by J. H. Hart, 
Esq., P.L.S., that this disease ora similar one occurs 
occasionally in Trinidad but is there not looked upon 
as serious and is generally ascribed to an excess of 
moisture. We have recognised the disease as occur- 
ring commonly in one of the West Indian islands. 
It is common and has produced much injury in 
Surinam, from which colony we have seen and ex- 
amined pods affected by it. 
Analyses were made of diseased pods, and the fol- 
lowing gives the composition of the dry matter of the 
whole fruit of the variety “ Forastero” in a healthy 
and in a diseased state 
Healthy. Diseased. 
Organic matters 
95 93 
94-43 
Phosphoric anhydride.. 
■81 
•59 
Sulphuric anhydride . . 
•18 
•19 
Sodium chloride 
•06 
•11 
Iron peroxide 
•05 
•04 
Manganese oxide 
traces. 
■01 
Calcium oxide 
■22 
■27 
Magnesium oxide 
•65 
■69 
Potassium oxide 
203 
2-85 
Sodium oxide 
•03 
■40 
Silica 
•04 
•58 
100-00 
99-98 
Taking into consideration that the healthy fruits 
analysed were quite ripe whilst the diseased ones 
had only attained about two-thirds of their normal 
development, the variations in the analytical figures 
have but little significance. As the contents of nit- 
rogen and of the mineral constituents derived from 
the soil varied but little in the two oases, probably 
the prevalence of black cacao in any place is not 
connected with defects in the composition of the soil. 
Wherever we have seen it occurring the diseased con- 
dition has appeared to be closely connected with an 
undraiued condition of the soil or with dampness 
resulting from over-shading and over-crowding the 
trees. We consider that the remedial treatment con- 
sists in the proper drainage of the soil and judicious 
pruning of both the cacao and shelter trees to let 
a Containing nitrogen ., 1A2 1’64 
in light and air. All affected pods should be sepa- 
rated from the apparently healthy ones, broken at 
a distance from the trees and the husks either burnt 
or else treated in heaps with quick lime an covered 
with soil. As an alternative the husks might be 
treated with a solution of half a pound of sulphate 
of iron (green vitriol) to one gallon of water or with 
Bordeaux mixture, but we are satisfied that the destruct- 
ion of the pods by burning is the most effective process. 
When trees are at all badly affected it may be 
advisable to spray them with Bordeaux mixture pre- 
pared in the following manner: — Dissolve six pounds 
of copper sulphate (blue vitriol) by suspending it in 
a coarse cloth bag near the surface in four gallons 
of water contained in a wooden or earthen vessel. 
Slake six pounds of quick lime (do not use air slaked 
or agricultural lime) in four gallons of water ; mix 
the two and when thoroughly mixed, insert into the 
liquid the freshly polished blade of a knife and leave 
for a few minutes. If the blade then shows a cop- 
pery discolouration more lime must be added until 
upon immersion it ceases to do so. Dilute the mix- 
ture with water to about 40 or 45 gallons. 
We give this receipt as the mixture may be found 
efficacious in fungoid diseases of fruit and other 
crops of which the smuts so common on mango and 
orange trees may be mentioned as instances. 
There is nothing here to help us in regard to 
the subject of Mr. Carruthers’ investigation ; but 
all through the Keport under review, a great 
deal is made of trainage and clearing the soil, 
and also of “judicious pruning.” But we do 
nob think that Ceylon cacao planters have failed of 
their duty in respect of any one of these particulars. 
OUR MAP OF THPl PLANTING DISTRICTS 
OF CEYLON. 
A PEW OP THE TESTIMONIALS RECEIVED. 
H. E. THE GOVERNOR. 
His Excellency desires me to convey to you 
his thanks for your new Map of the Planting 
Districts, which will be most useful. It is in fact 
just the sort of thing we have been wanting for 
some time.— Yours truly, 
,Ti. , r, ^ Ward Jackson. 
IheCueens House, Colombo, 7th Dec. 1897. 
FROM AN OLD SUBSCRIBER. 
I must send you a few lines to wish you a 
merry Christmas, and thank you for the new map 
of the Estates : its arrival h.as been one of the 
events of the week. Long-looked-for, come at last. 
Although I don t know all the districts, and am 
therefore no authority on the geography of Ceylon 
estates, yet so far as I do know, I think it is 
beautifully done and wonderfully accurate The 
marvel is that you have been able to produce 
so useful a map of the planting districts and 
issue it at the low figure fixed. One would 
think that you expected to sell them by the 
thousand before they could pay you for the 
trouble and cost you must have let yourself in 
for, to produce such a map. For my own part 
I thank you very much for undertaking the work 
and congratulate you on the result, and hope it 
may piove, as it deserves to be, financially a 
success. — Yours faithfully, 
, 1.T r. „ , ^ A Subscriber. 
MataleN.E., 26th Dec. 1897, 
FROM “TIMES OF CEYLON,” DEC. 15TH. 
We have to acknowledge receipt from the 
i bserver Office of a new large map of 
the Planting Districts of Ceylon, brought 
up to date, and such as ]dauters and 
others have long needed. The map, which 
