June 2, 1902.] THE TEOPICAL 
AGRICULTURIST. 
791 
fruiting form cf the fungus or ascigerous state. This 
form I am iuvesfcigating, and it will form the subject of 
a paper of a more technical character than is suitable 
in these Circulars From a planting point of view 
this discovery is most interesting, as it points to one 
method this fungus has of perpetuating itself. All such 
cases, which can be seen by the discolouration of the 
young shoots and the absence on them of any flush, 
should be treated by pruning these young shoots back 
and burning the prunings. A case has occurred of 
the Gray Blight fungus attacking the youngest beds 
over a v.hole field and reducing the yield to a grievous 
extent. 1 cannot say whether in the cases 1 have exa- 
mined the buds were " bauji " by which I mean buds 
tue growth cf which has been checked, or whether they 
were attacked when in their earliest stages. 
If the buds are " bauji " tbey may have been on the 
bush for sometime — long enough for tJtie growth of the 
fungus as it generally occurs ; and further it is pro- 
bable that the presence of the fungus in the buds may 
itself have produced a"banji," This phase of the 
Gray Blight fungus is, however, still being investigated 
and I may hope to learn more of its nature on visiting 
the area affected and noticing the conditions preva- 
lent there. 
The efforts cf the Gray Blight fungus in this 
direction to decrease the output of tea should be care 
fully watched and by pruning lightly below the in 
fected places, stopped btfore it becomes at all common" 
KOOT DISEASE OF TEA. 
A Disease which is more difficult to fight, and which 
has more disastrous effects in the places where it 
occurs, is the root disease of tea, which is to be found 
in many districts, more especially those at higher ele- 
vations, wheie the disintegration of dead vegetable 
matter is slower than in the low-country. 
This is caused by a fungus, most probably Rosellinia 
radiciperda, Masseethongh in almost all cases there are 
not present the fruiting parts of the fungus, by which 
alone it chii be ceitainly identified. 
The mycelium of the fungus commonly called 
" "W hite Koot-rot, " can be noticed as white thread- 
like strandF, easily seen with the naked eye. When it 
has permeated the root entirely, it often assumes a 
fan-like shape covering the surface of the root, and can 
be easily detected on scraping away the dirt and the 
outer surface of the root. The majority of known fungi 
are saprophytic, ie., living on dead and deoa.ying sub- 
stances ; others are parasitic, i.e., growing on the 
living tissues of plants or animals. In some cases 
fungi have the power to exist in both ^hese ways, and 
the tea root disease fungus is one of this latter kind. 
It begins its life as a saprophyte on any dead timber 
of a suitable kind. The softer and more spongy roots 
of trees like Sjmplocos,, when the tree is cut down, are 
an ideal home for this fungus 
I have found it growing on various jungle roots, — in 
most cases it is not easy when the tree has been cut 
down for sometime to certainly determine the species 
of the root,— on buried logs, and prunings of all sizes, 
even no thicker than a slate pencil. 
Having grown for some time om these dead hosts, 
when moisture is present it spreads out in different 
directions until it encounter? another piece of suitable 
food. Unfortunate. y for the cultivation of tea it h.as 
acquired the liking for the living roots of tea bushes. 
The mycelium can grow to a considerable dislanoo 
through the soil if damp until it reaches ihe next piece 
of nutritive material. I have observed a strand of my- 
celium ?\ inches in length which had apparently no 
intermediate host in its growth from a piece of dead 
Syinplocos root to a young root of tea. It must be 
borne in mind that the presence of moisture is neces- 
sary for the growth of this fungus, and also that when 
it first reaches and attacks the root of living tta the in- 
jurious effect to the plant is not noticeable. 
From a large series of observations I believe that iu 
the case of vigorous tea a bush may be affected for two 
years or longer without succumbing. The tea bush is 
a hardy plant and makea a good fight against such an 
enemy, but it is hardly possible that if once the fungus 
has got a foothold on its roots it can ever throw it off. 
I have seen this fungus killing out gr;iduaily some of 
the finest tea bushes in a field, and it will generally be 
seen th it whc-u one bush is badly affected and almost 
dead, some of 'he bun ouuding bushes are unhealthy 
and show signs of suii'sring, though in a less degree, 
from the same evil. 
The remedies which should be employed to prevent 
spread of this di-ea^e are simple, ,■ nd where carried 
out thoroughly have ia all cnses lessened and should 
eventually urive out the fungus. 
The out ing of d'-ains not lei-s than two feet deep by 
one bioid has tlie double effect of removing moisture 
from the soil and isolating the patches of disease, as 
the fungus mycelium cannot pass over a space of one 
foot, and if these are kept free from decaying matter, 
it will be stopped in its progress. 
The burying of prunings iu infected areas is danger- 
ous and should be discontinued, as by this means the 
fuugus has no other food than the roots of the tea and 
may be starved out. 
The use of lime is unSoubtedly a deterrent to the 
progress of the fungus, but since it is not possible to 
effect the application of liaae so that it is in contact 
everywhere with the mycelium of the fungus, it is not 
always successful, I have been told by a careful 
observer that he has noticed a piece of lime round 
which the stra nds of this fungus were wrapped, and I am 
at present exnerimenting on the action of various 
proportions of lime in cultures of this mycelium. 
All bushes which are killed should be carefully dug 
out, leaving none of the root if possible. The hole 
should be exposed to the air if the weather is fairly 
dry, and before filling in an application of lime should 
be made. 
The ditches or drains should be dug around a larger 
area than is observed to be diseased, as some of the 
surrounding bashes may have the fuugus in their roots 
though not noticeably diseased. 
It may be noted as an encouraging feature in the 
case of this fungus that it rarely produces its spores 
undei ground, and seldom reaches the surface, and 
therefore almost its sole means of spreading itself is by 
the running through the soil of its mycelium or vege- 
tative portion. 
Cacao Canker and other Disease. 
Passing from tea to other cultivated plants, a 
leaf disease of the coconut palm has been studied, 
which bears a close resemblance to Gray Blight ia 
tea, though it is undoubtedly distinct, and does, 
happily, not do very much damage to this valuable 
products. 
The canker of cocoa has been somewhat fully dealt 
with in a Circular discussing the whole question, and it 
may be mentioned here only briefly. No new p hases 
in the workings of this disease have been found, and 
the cures and prevention where used have coniiuued 
to rep^y 'hose carefully carrying them out. It is still 
a subject f jr regret tiiat larger areas are untreated, and 
that in these places the fuugus prospers and spreads 
both on pod and tree. 
It may be that this report will reach some cacao 
planters who may not have read the circular 
" Cacao Canker in Ceylon, " pub ished in October last, 
and for these it will be well to repeat the summary of 
measures which are, 1 think, very generally considered 
as effective : — 
" Prevention. — Regulate the shade so that the sun 
and air can reach all parts of the cacao tree.s, and keep 
the cacao from being so close as by its own leaves to 
densely shade the ground. 
"Prevent dampness by surface draining, especially 
in low hollows. 
" Allow suckers to grow on all trees that show any 
sifjn of disease. 
"Burn all dead cacao trees and branches. 
"Burn all discoloured pod husks from wh.ateVei' 
cause they are discoloured. If this i« no^ possible 
bury with lime,' 
