7 
Several new plantations set out between l OOS—1910 are just coming into bearing but the 
crop obtained from the small extra number of trees is rnore than counterbalanced by severe 
outbreaks of diseases which go far to reduce the crop year by year. I'he bulk of the new 
plantations was however set out after 1910 and are not yet in bearing. 
It is probable that the cause of the reduction iu tlie crop referred to last year viz., under¬ 
bearing following overbearing of umnanur’ed trees iu 1914, has also shown its influence in 
1916. It is well known that coconut palms luvelop slowly their vegetative organs and that 2 
years and 9 months elapse between the time wuen the embryo leaf is formed in the growing 
shoot until the time when the cluster of the nuts borue by it comes to maturity. For this 
reason it is probable that any disturbance in the physiological conditions of coconut palms 
shows itself, one way or the other, during at h, „ L'wo cone 'utive years. The crops for 191-5 
and 1914 were good and considerably in excess of '■ j ) • ■:', ■ bug crops. It is likely that the 
resulting diminution in the crop for 1916 v/o-. rep: -in 1916. 
The factor disease was investigated duriog the ye;ir. in November a whole week was 
devoted to a tour round Mahe. A report was so>; , ited to His Honour the Administrator on 
the subject and extracts from it are about to be published. It was noticed that the beetle 
disease was in the Southern districts more virulent than in other districts while the following 
other diseases were come across everywhere.:— 
1. The stem disease caused by melitomma insulare already referred to. 
2. The stem bleeding disease caused by the fungus (Thievalopsis). 
3. The little leaf disease. 
4. The leaf disease caused by the black barnacle scale (A.spidiotus ficus). 
5 The leaf and nut disease caused by the white fluffy scale (Ohionaspis inday)» 
6 The leaf disease caused by the cinnamon scale (Lecanium tesselatum). 
7. The leaf base disease caused by the white barnacle scales (Aspidiotus lataniae and A. 
dictyosperma). 
8. The yellow leaf disease caused by a new scale (Aspidiotus Ansei). 
9. Last, but not least, a physiological disease caused mostly by shade and lack of food in 
the soil. 
No specifle symptoms of the bud rot disease was found although brown and black spots are 
very common on the young inflorescences, leaf bases and swords. We shall have to be on the 
look out for this disease which has been found occurring in India, East Africa, Ceylon and 
which is responsible for the aimihilation of the coconut industry in Cuba. It is brought about 
by diflferent organisms. In India by a fungus (P 3 rthium) and in Cuba and West Indies by a 
bacterium (bacillus coli) which also attacks men and animals. The disease has been success¬ 
fully inoculated by Joluison from animals to coconut palms. It may be caused by other or¬ 
ganisms not yet identified. From a practical (although unscientific) point of view this variation 
in the causative organism is, I am afraid, a sign of the disease being some sort of ultimate 
effect of other unchecked diseases combined. 
The disease caused by the militomma beetle is the worst of the lot for the present. It kills 
the trees'gradually ; trees of 20 years being more affected than the others. When the attack 
is severe a young tree is killed out in 2 years but when there are only a few grubs of the beetle 
present the coconut trees resist for years, but being weakene'l, it becomes the prey of other 
diseases. The destruction of the melitomma beetle is imperative and as long as this beetle 
disease will occur in the Colony the treatment of the other diseases will be made in vain. A 
tree is killed in full bearing at 20 years when it is worth Its 20. It would cost only 20 cents 
to save it. A few estates of 100 acres have lost 50o/o of the trees within the last 20 years, i.e., 
250 trees per aimum worth Rs 5000. The beetle attacks trees which are not well planted. As 
it is vmable to fly a long distance the eggs are deposited near the ground in cracks of the stem 
generally caused by aerial roots emerging in neglected plantations. It is easy to remove the 
grubs by excision of the diseased tissues containing them and tarring over or liming heavily 
the wounds. The insect is not found attacking other plants. 
All the scale insects diseases are very virulent just now but the Aspidiotus scales are 
parasitised by Cephalosporium levanii which is a beneficial fungus doing more work than 
that which could be done by spraying and otherwise. It is imperative to spread the leaves 
harbouring the beneficial fungus over all the plantations and to destroy by fire the leaves free 
from them. The new scale Aspidiotus Ansei attacks the heart leaf before it is expanded in a 
few localities but it is quickly spreading all over Mahe. From the fact that it attacks vigo¬ 
rous organs such as heart leaves, one can deduce how uncommonly virulent this insect is. 
After the leaf opens, the leaflets are discoloured all along the rachis (midrib) and presents a 
characteristic bright yellow colour which shows at a considerable distance. At the present, 
stage of the disease one can only burn the attacked plants on the spot and put under obser¬ 
vations the neighbouring palms to prevent any new outbreak. 
In destroying leaves by fire on trees still standing great care should be exercised in not 
flaming young trees which are not woody enough to prevent sap from exuding after treatment. 
Only old trees (above 40) should be flamed. Trees of all ages when flamed are however 
more attacked by scale insects than other trees. In many cases I have seen flamed trees har¬ 
bouring the flutfy scale (Ohionaspis inday) or tender leaves which had just expanded while 
generally speaking only mature leaves are attacked by this insect. 
Sickly trees, grown under shade and unmanured, are also predisposed to scale insect attacks. 
Manured trees harbour much fewer parasites. This is much in evidence at the Botanic Station 
where, among other plants attacked by scale insects, it has also been found that Pandamus 
trees growing in moist soil under natural conditions are free from Hemichionaspis aspidistras 
scales while the same trees growing at a short distance from the spared trees in rocky banka 
are handicapped by the same insect to a large extent. 
