708 
THE TROPICAL AGRICULTURIST. 
If this were generally done, an immense decrease in the amount of " grey blight " in the 
Island would no doubt result. It is, however, the lack of co-operation in these sanitary matters thai 
vitiates the good work done by the few. 
Though the climatic conditions have not been at all unfavourable to the growth of fungi, yei 
the amount of grey blight on growing tea has not increased, and in many localities has lessened to £ 
considerable extent. This may be to some extent explained by the measures taken by not a few ir 
burning or biirying with lime diseased leaves and so destroying vast quantities of spores, and also tc 
the close pruning of some large areas of badly affected tea. 
A less encouragixig circumstance with regard to " grey blight" is that I have found it on th( 
leaf stalk as well as on the leaf. Specimens of such diseased stalks have been collected and sent tc 
me from various localities, and on them the fungus and its characteristic spores were abundant. 
This calls for careful observation on the part of planters, as it is most important that any bucI 
attack should be at once stopped by pruning back the bushes below the browned and diseased parts 
and carefully burning the primings. The chief reason why " grey blight" has not done more harn 
to tea is that, as a rule, it only attacks the leaf, and when the diseased leaves fall the bush is fre( 
from disease ; were it to spread to the permanent portions of the plant it would become a more seriouf 
enemy. It will be of advantage if any planter finding the leafstalks discoloured, and suspecting thif 
to be due to grey blight, will at once forward specimens for determination. 
Another leaf fungus, Gladosporiumherharum,V(i\'fi., was foimd on the leaves of tea bushes amons 
which Liberian coffee was growing, I observed on the coffee leaves (which were also attacked b^ 
Hemileia vastatrix, Berk.), a disease which produced the concentrically marked grey patches asso 
ciated with grey blight. On examination this proved to be due to another fungus, the Cladospoi'iun 
mentioned above, and on investigating similar patches on the leaves of neighbouring tea bushes thii 
same fungus was found, Cladosporium lierharium is a common fungus on dead plant tissues, bu 
also occurs as a parasite on the living leaves of many plants ; it is recorded on such varying hosts ai 
wheat, peas, apple, raspberry, cycads, agave, and pine seedlings. It has a greenish grey septatf 
mycelium and oval conidiospores. 
A rej)ort was sent on a leaf disease on tea which is common both here and in Indian tej 
districts. It is caused by a lichen, Ceplialeurous mycoidea, Karsten, which produces characteristh 
reddish and white or grey spots on the leaf ; it is partially parasitic, but it does very little harm anc 
can spread only very slowly, and is consequently not a matter for such serious attention as a fungu 
parasite. 
A root disease of tea has been investigated in regard to its habits and the best method 
of combating it. It is caused by a fungus, Rosellinia radiciperda, Massee, and most frequently founc 
in clearings where the stumps of jungle trees are left, more especially those with soft wood, but an^ 
decaying wood under ground either of stem or root, if the soil is in a moist condition, may be th 
harbourer of this fungus. It has been found in Ceylon on stumps of various jungle trees, bariec 
logs, stakes put in beside young plants, and buried prunings ; from these it frequently spreads to am 
invades the roots of living tea bushes, and when it has once attacked a tea bush it graduall; 
decreases the vigour of the plant, and in the end, as a rule, kills it. It can be recognized by its whit 
felty mycelium, which forms strands as thick as or thicker than a piece of cotton, and runs undergroun( 
from one host to another. 
The fruit — which is not so commonly found underground, but can be seen on pieces of woo( 
which have been on the surface after it has been permeated by the fungus for some time — is blacl 
and consists of numerous globose bodies. 
The best preventive means against the spreading of this root enemy — as indeed against man; 
other root parasites — are to take out the dead or dying bnsh, burn the roots, thoroughly lim 
the hole, also to cut a trench not less than two feet deep round the bushes affected, not only round th 
dead one, but those neighbouring which may be attacked in a less degree, in order to isolate the pate 
from the rest of the tea bushes. Lime forked in the infected patch will often kill the mycelium an 
save some of the other bushes. The trenches also have the effect, if properly cut, of draining th 
place and so removing the conditions which favour the progress of the fungus. 
This disease is fairly common in various districts, in some cases three or four supplies i: 
saccessioii having been killed where the new plant has been put in without taking out the old root^ 
It, however, is generally very local in its effects and rarely occurs where the soil is thoroughl 
drained. In fields where it is found it is inadvisable to bury any prunings until the disease is entire! 
eradicated. 
An experiment with regard to the treatment of isolation and liming the infected area wa 
carried out on an up-country estate with encouraging results. A trench two feet deep and one foe 
wide was cut round a patch on which one bush had been killed by the attacks of Rosellinia and som 
