193 
THE TROPICAL AGRICULTURIST. 
rSEPT. 1, 1899. 
We now take over wheat Mr. Masses has 
to say on Cacao and Coft'ee diseases. As re- 
gards " Cacao," we are told of : — 
CACAO POD DISEASE. 
{Phytophthora oninivora, De Bary.) 
This disease has been recognised for some years past 
but has recently become much more general and de- 
structive to cacao pods in Trinidad. The same fungus 
is probably the cause of the cacao pod disease in 
Ceylon. 
The symptoms of disease are a darkening of the 
' shell' of the pod, which almost invariably commences 
at one end, and gradually extends over the entire 
surface. After a while the fruit of the fungus shows on 
the surface as a delicate white mould, often appearing 
first in the furrows on the surface of the pod. 
The white mould represents the conidial form of 
reproduction, and lasts for some weeks, the numerous 
conidia produced being carried by wind to other pods, 
which in turn become diseased. 
The mycelium of the fungus permeates and destroys 
the entire substance of the pericarp or ' shell,' and 
often also attacks the seeds. Numerous resting spores 
are formed in the diseased fruit, and are liberated 
when the tissue decays, when they germinate and 
start the disease the following season. 
Preventive Means. — Spray with dilute Bordeaux 
mixture, commencing when the fruit is quite young, 
and continue at intervals as required. 
Bemove all diseased fruit from the trees, as when 
once attacked it ia valueless, and only serves to spread 
the disease if allowed to remain. 
Do not allow diseased fruit or shells ' to remain on 
the ground in the plantation, as the commencement of 
the disease each season depends on resting spores 
present in such material. 
The fungus is known to attack a large number of 
di^erent plants ; and it will be important to ascer- 
tain whether it is present on other plants in the 
neighbourhood of the plantation. Seedlings are often 
attacked. 
The disease is most abundant in low, damp situations, 
or where the trees are much shaded. 
Masses, Kew BuUetin,l899. 
CACAO DISEASE. 
Mr. J, B. Carrnthers, who has spent some time in 
Ceylon investigating the destructive disease attacking 
the cacao tree, has published his report, of which the 
following is a summary. The name of the fungus 
Causing the disease is not given, but the account leaves 
little doubt that it is a species of Nectria, allied to 
the species causing canker in the wood of the 
apple tree. 
The first indication of disease is a darkening of a 
patch of the cortex ; i£ this patch is cut out it is found 
to be soft and of a claret colour and full of moisture. 
At a later stage minute white pustules appear, especi- 
ally in cracks ; these eventually become pink. During 
the white stage very minute oval conidia are produced 
in immense numbers, and later on larger, crescent- 
shaped conidia appear. Finally, when the cortex is 
dead, or nearly so, a third aacigerous form of fruit 
develops ; the sporangia being globose, crimson, and 
grouped in clusters. 
The disease often spreads rapidly ; in one instance a 
diseased patch more than two feet long, and reaching 
almost round the tree, had formed ten days after 
inoculation. 
Preventive Means,— The most satisfactory method 
is to cut out the diseased patch, along with a margin 
of apparently sound cortex. Covering the wound with 
tar is not recommended. 
Carruthers, The Tropical Agriculturist, Nov. 1, 
1898, p. 359. 
Finally, here is how our poor old coffee and 
its bitter fatal foe are treated : — 
_ COFFEE LEAP DISEASE. 
(Jlemileia vaatatrix, Berk, and Broome.) 
This terrible scourage, which was first observed in 
small quantity on a single estate in the Madulsima 
district, which occupies the south-western portion of 
the hilly country of Ceylon, ia now widely distri- 
buted — India, China, Malay Peninsula, East Indies, 
Philippines, ISIatal, German East Africa, and probably 
wherever coffee is cultivated in the old world. 
The leaves are most frequently attacked, spots being 
also sometimes present on young shoots and even on 
the fruit. 
On the leaves the earliest stage of the disease is 
indicated by the presence of more or less circular, 
discoloured spots. These continue to increase in size 
for some time, retaining their irreeularly circular 
outline, become pu.le yellow, and studded with bright 
yellow clusters of spores, which soon change to • 
bright orange colour. The patches show on both 
surfaces of the leaf, but the spores are confined to the 
under surface. 
The spores are produced in dense clusttrs on the 
tips of hyphae which come to the surface of the leaf 
through the stomata. Those surfaces of the spore 
that are in contact when the spores are growing are 
smooth, whereas the outer, free portion of the surface 
is coarsely warted. 
Preventive Means. — Very little success in this 
respect attended the eSorts of those investigators of 
the disease, whose primary object was to discover, 
if possible, some means of checKing the epidemic. 
Probably some of the modern fungicides, as Bordeaux 
mixture, etc.. might prove more effective. Diseased 
leaves should be collected and burned on all 
occasions. 
Full notes respecting the distribution of the 
different species of hemileia, along with the dangers 
arising from want of discrimination in the selection 
of ' shade trees,' will be found on page 27 of this 
book. 
Berkely, Gard. Chron., p. 1157 (1869.) 
Morris, The Coffee Leaf LHseaieof Ceylon and Southern 
India. 
Marshall Ward, Sessional Papersi, xvii., Colombo, 
Ceylon, 1881. 
There are also two other '* coffee diseases " re- 
ported, the account of which we may as well 
quote : — 
COFFEE TWIG DISEASE, 
(Necator decretus. Ma-see.) 
Bursting through the epidermis of young shoots as 
minute white spots, which soon become orange-red and 
gelatinous. Said to be a destructive parasite on 
coffee trees at Singapore. Commencing at the tips 
of young branches and extending downwards. Re- 
moving diseased branches checks the spread of the 
disease, 
Massee, A'ec; Bulletin, 1898, p. 119. 
AMERICAN COFFEE DISEASE. 
(Stilbum flavidiulu Cooke. 
—Pistillina flMvida, Speg.) 
This disease is [almost as destructive to the coffee 
industry in the New World as Hemileia vastatrijc is 
in the Old World. 
The symptoms of the disease are unmistakable ; 
circular whitish blotches occur on the leaves, often in 
considerable numbers, and are equally marked on both 
surfaces. Using a pocket-lens, very minute fungi re- 
sembling a minature pin in shape, and of a clear yellow 
colour, can be seen grouped on the spots on the upper 
surface of the leaf. The berries are also sometimes 
attacked, being marked with circular spots. On the 
young shoots the pale diseased spots are elongated. 
The disease occurs in Costa Rica, Venezuela, Guate- 
mala and New Granada. 
Preventive Means. — Although by no means a new 
disease, no serious attempt appears to have been made 
to arrest its progress. Being quite superficial, it is 
quite probable that spraying with Bordeaux mixture, 
or with ammonical solution of carbonate of copper, 
would prove effective. All diseased leaves and fruit 
should be collected and burned, otherwise spraying is 
of little avail. 
Stilbum FLA viDUM, Cooke Grcv., 1890, p. 11. — Form- 
ing circular bleached spots on living leaves, the bleached 
patches pass quite through the leaf ; sporophores occar 
on upper surface of the leaf, gregarious on the patches, 
very minute, entirely clear yellow, 1-2 mm high, stem 
