824 THE TROPICAL AGRICULTURIST. [June 1, 1900. 
NOTES OF OBSERVATIONS OF SOME TEA 
DISEASES. 
At a late meetinj? of the A mbagamuwa _ Plan- 
ter's As.«ociatlon (Ceylon), under die iiresidency 
of Mr. Hutchinson, the following paper wa^i 
read by Mr. Olivkr Collutt : — 
In a paper on the 
PREVENTION OF TEA. PESTS, 
which I had the honour of reading before this 
Association last year', one or two suggestions 
were made which attracted some attention at the 
time, and have since, in the case of a number 
of estates, been put into general practice. These 
related to the importance of removing moss from 
the stems of the bushes, of resting, poor and 
weakly plants and of generally paying more at- 
tention to the condition of individual trees, witli 
a view to increasing their power of resistance 
against disease. 
' I now offer some further notes of what 1 have 
been able to observe of the nature and charac- 
teristics of some of our more prominent tea 
diseases and of their modes of attack, in the 
hope that they may serve as a contribution 
towards a more general knowledge of the subject. 
It is, I think, now generally acknowledged 
that the 
MOST DESTRUCTIVE DISEASES 
by which Itea is likely to be affected, are those 
which beong to the order of fungoid or crypto- 
gamic parasites. Insect pests are of course, 
always with us, but as the harm they do is 
of a more or less transient nature and can, 
as a rule, be met by comparatively simple 
remedies, they are of less serious moment than 
those disease's which are due to the agency 
of parasitic fungi— especially as these latter, are 
very largely controlled as 1 am about to show, 
by the operations of climate and atmospheric 
conditions 
The two principaCl fungoid pests at present af- 
fecting tea are those commonly known as 
THE GREY AND THE BROWN BLIGHT. 
Grey Blight [Pestalozzia Guejpini) is, according to 
Dr. Watt, "one of the most destructive and 
dangerous of parasitic fungi to which the tea 
plant is liable." It appears to be more or less 
prevalent in every district of the Island, and is 
particularly noticeable upon wind-blown ridges, 
and upon "tea in exposed fields, where the soil is 
worn and poor. Its worst effects are, however, 
always seen upon bushes that have been too heavily 
plucked, and whose constitution has thereby 
become impaired. 
The spores of this fungus are widely dissemi- 
nated by winds in the dry season, and germina- 
tion usually follows as soon as wet weather and 
sufficiently moist conditions prevail. A prelimi- 
nary outbreak of the disease may be expected 
to appear, soon after the first April rains, but 
as a rule growth upon a large scale, does not take 
place until June, when wet and windy weather 
is continuous and the light is dull. Under these 
favouring conditions, a state of rapid infection 
and re-infection of the bushes is set up, and is 
prolonged throughout the months of July and 
August,— -the last-named month being as a rule 
that in which the climax is reached. 
Practically then, Grey Blight appears to be a 
MONSOON DISEASE, 
and it seems only tod probable that it will (if 
measures be not taken to withstand its progress) 
increase in virulence with every season. It would 
" * Tropi'.al Agriculturist, Oct, 1899, 
therefore seem that it is of the first importance 
for us so to trea^ our bushes that they may be 
prevented from falling into chat condition of he ilcli 
which invites disease. For we may safely assume 
that the power of each outbreak to cause per- 
manent injury to tea, will, in every instance, 
be in exacD |)roportion to the degree of vigour 
of the bushes at the time of the invasion. 
There seems good reason to believe that all 
plants— particularly those under cultivation — 
have much to contend with during the monsoon; 
!uid that in an abnormal season (such as that 
\vhi<!h we experienced last year) their natural 
resources are severely taxed. At this time, not 
only is there wind to carry the spores of disease, 
and continuous moisture to secure their rapid 
germination, but the dull light prevailing 
(lin;inishes the transpiration of the leaves (the 
tissues of which are now unduly filled with 
water) and by reducing their normal vitality 
predisposes tiiem to ready infection. 
Moreover, it has been observed that at this 
season the 
GI^OWTH OF THE FEEDING ROOTLETS 
of tea it suspended. This important fact which was 
first noticed in Ceylon by Mr. William Cameron 
of Ythanside Estate, is without doubt, one which 
will have to be taken into careful consideration 
in connection with the operations of pruning, 
manuring, etc. in different districts. It will 
probably be discovered (as Mr. Bamber 
has already suggested) that the seasons of root 
growth and decay vary to some extent in every 
part of the Island ; and caiefuUy recorded data 
from different localities would prove of the utmost 
value. In Ambagamuwa, I find that the rootlets 
die back in May, and commence to grow again in 
September ; but my experiments in this direction 
are as yet far from being conchisive. It is curious 
that very little is known of this phenomenon up 
to the present time. Mr. Willis of the Peradeniya 
Gardens tells me that no observations have been 
hitherto recorded in Ceyloi regarding it ; though 
he points out its great significance in connection 
with the question of mainiring. Ic is, for ex- 
ample, obviously inadvisable to manure tea at a 
time when its feeding rootlets are not in a proper 
condition to as.similate it. 
The actual effects of an attack of Grey Blight 
upon tea have been as yet very imperfectly ob- 
served in Ceylon. In some instances, an attack 
of the disease which has almost denuded the trees 
of their foliage, has been followed, after the mon- 
soon, hy healthy flushes, which might lead one 
to suppose that the blight had acted in the form 
of nothing more than 
A SUBSIDIARY PRUNING. 
In other cases — especially where the trees have 
run too long from pruning — they liave shewn little 
power to withstand the effects of the attack ; and 
liere it seems likely that the result has been per: 
manently harmful. It is at least very noticeable, 
that Grey Blight does not attack young and 
succulent leaves ; and the inference appears to be 
that more frequent pruning may tend to keep 
this disease in check. 
In the case of 
BROWN BLIGHT 
(CoUetotrichum cmne'lice) the situation is some- 
what different, and at i)re.ieni, i am inclined to 
regard this as the more serious disease of the two. 
i'or .vhile gtey blight is practically confinen 
(as just stated), to the older leaves of tea, browd 
Ijlightis frequently found upon the younger growth 
(though not upon the flush itself), and it often 
