August i, 1891.] 
the TROPICJO. A'OnrOOLTUmST. 
II7 
As the work of doBtruction is carried on w-ithin the 
leaf by the niyceliinn, it is quite evident that remedies 
anphed after the spores appear on the epidermis of 
the leaf aro UBeless : they must destroy the tissues 
to reach the foe within. Any agent to be of uso 
niUHtbo on the leaf before the spore finds a resting 
place on it. ^ 
When experiincnting on the development of the 
spores on a coffee leaf, I took a clean ReotUing and 
prepared on TyndoJl’s method, 
With the result that 1 got a plant free from leaf- 
disease growing m sterilized soil. The spores only 
nowhere else, and 
Mr. Marshall Ward’s results wore fully bornoout. The 
aiBease is not constitutional : the spore of the parasite 
must be deposited on tbo leaf before the disease can 
appear. 
A weak tree suffers more than a strong one from 
Jne loss of Us leavoR ; and a tree weakened by injury 
to Its roots, due to romovaJ of the surface soil by 
wash mamoti© digging, or other causes, recovers less 
apidiy^ and if the attack of leaf disease or succcs- 
sion of attacks are virulent will in all probability 
uccumb. 1 he lower the vitality of the tree attacked 
A chance of recovery. 
A half ‘Starved coolie readily falls a victim to fever, 
oiera Ac., while if well fed ho more easily resists 
ne attack of disease ; so it is with the coffee tree, 
nf ti most favorable to Ihedevclopement 
me spores ar© a close, steamy, hot, stagnant 
atmosphere, with a subdued light, 
io followed by hot days, if a dense shade 
over the coffee, aid in the fructification. 
As a rule leaf disease is bad in South Coorg twice 
a year : just after the early ruins, and during the 
utunm showers. In the hot weather wo are practically 
ee iroin it, though I have found the disease spots 
every month of the year. 
onauo under which the coffee of South Coorg is 
growji affects the disease in two ways. 
f f. as a wind screen and retards the passage 
J^®.®Poros from one estate to another. If the 
ueo IS one continuous sheet the disease may start 
estate and roll right over it 
Pen the climatic conditions are favorable. 
have visited an estate on the first of the month, 
ana though loaf disease was to be seen, it was not 
suffering to any e.xtent; fourteen days after the estate 
was rod from end to end, and by the end of the 
Pionth it liad resumed the appearance presented at 
the beginning. 
Ihia estate suffered from these periodical attacks, 
Which always began at one corner, and sw’cpt over 
he estate in regular progressmn. 
Mirther examination showed^ that it w’aa not the 
♦ u ^ ^^I'ato affected in this way; and in every case 
® point of the attack was where the shade 
thick, Avith damp and sour ground below. The 
iu the early morning laden with 
with often not a breath of wind. As the sun 
possible conditions for the develop- 
tH play. 
thir*ir did more harm tnan good ; being too 
consorved^t^A^”*'^^* admission of fight, 
aidod to an undesirable extent, and 
necessSrfrfr of the moist heat 
TTnrt ° 8«ri»inatiou of the spores, 
was firsf tho course to be pursued 
funciis hv conditions unsnitablo to tho 
Irbiif?. ’^^hulatmg tile shsde, and draining the 
land; then apply the remedies. 
for rll?' leaves of tlxe tree suf- 
on !l,o I’ro fe»tin«place of tho spores is 
inir tu (lead and dying leaves rest- 
coolies pick up spores and dust 
as they walk threugh tho coffee, Lid the bulk of 
the spores find a rcstingplace on tho lowest leaves. 
Ihese are shaded by the upper branches and in- 
'“oiBture evaporated from the 
If '*^‘1 general there are not only more 
spores on tho lower loaves but tho closer they are 
for more favorable tho conditions are 
lor the development. 
UnlcBB the ground and the jungle trees aro treated, 
ay nothing of the neighbouring estates, it will 
»g uuposBiblo to eradicato leaf dweasc. 
But an estate can be kept practically clear of tho 
pest by one application to the ground and two to 
the leaves per annum. 
In P’rauco remedies are applied to the vine four 
times per annum with great success. The work is 
not expensive; only labour must bo there to do it at 
tho right time. 
The IJtviileia vasiainx or a fungus so closely 
allied to it that I can see no difference notween them 
is to be found on at least three jungle trees. Un- 
fortunately I know next to nothing of ootany, so can- 
not classify thorn. It was on tho goni {Ficus 
mijsoT€nsis7) that I first found tho spores: whether 
these are the uredo spore or the second sort 
of spore which prefers another host I am not sulfi* 
contly well up in cryptogamy to determine, but 
tho spores taken from tho goni and soavu on tho 
coffee leaf developed there, 
I had a few failures, in transferring the spores from 
the coffee to tho goni, but on the whole, results were 
satisfactoiy. Tho atty {Ficus gfomerato) when a 
young plant was taken could also bo infected. If 
tho loaves are old, the yellow spots may show in the 
leaf, with but very few spores Doing formed. 
Liberian coffee, which has a much tougher loaf 
than tho Arabian, displays much the same characters 
as tho atty and goni. 
Tho damage done by the' llemilcia vastatrix is en- 
tirely that of depriving the tree of its leaves. You 
can make a coffee tree sick by varnishing its leaves 
on the undersurface and so xireventing its breathing: 
consequently in selecting a remedy care must be 
taken that it does not clog up the pores of the 
epidermis. It would do more harm than good. Strip- 
ping off tho diseased leaves ranks in tho same category. 
A tree must have its leaves which are its lungs 
in good order or it cannot develope its fruits. If 
all tho blossom that appears would set, crops of from 
five to ten tons per aero would be common. As a matter 
of fact only from one or ,two to ten per cent set, 
and all of that does not come on. 
The true uso of a manure is to enable the tree to 
set its blossom, and to assist in the developenient 
of a healthy bean. My experimental plots being 
systematically manured wore able to set a larger pro- 
portion of the blossom than tho estates, though both 
received tho same work, tho only difference being in 
the manures and — Though pruned and 
handled down to tho level of the estates, they had 
a finer show of leaf and wood, and recovered from 
an attack of leaf disease more rapidly. 
The resnlts from the estate wlioro leaf disease was 
worst, taking the crop of 1887-8 as the basis and 
stating results as percentages on that, for both plots 
and estate, wo got the following result: — 
Year 1887-88. 1888-89. 1889-W. 1890-91. 
Estate 100 6.8*1 34*2 8*5 
mot 1(X) 90*9 239-.5 36*3 
This shows the value of steady systematic manuring 
broadcast annually, and this year the plots have a 
splendid crop on them. 
It requires time, patience, and careful observation 
to get reliable results, and the results to be of value 
must form a series obtained by steady systematic 
Avork. Not knowing how the various manures would 
act on tho coffee tree I began with only small plots 
of 3,200 trees, or rather tho space occupied by that 
number when tho estate was originally planted. 
Each manure acted on two plots oi 100 trees each, 
and tbo results individually taken are not conclusive. 
Therefore I had to take for comparison the aggregate 
results, including good, bad, iuuiffercnt and the un- 
mauured plots for comparison with the estates, which 
in most cases did not receive tho manures I re- 
commended, owing to failure of the supply of fish 
and other causes. 
Now as to preventative measures. Steady systematic 
manuring annually holds the first place ; drainage it 
in soino cases quite as important, and the careful 
regulation of shade render tho conditions under 
which the coffee is grown suitable to it, and 
unsnitablo to the fungus; then special remedies 
can bo successfully applied. 
* A word which caunpt hg out,— Eo.T.A, 
