92 
THE TROPICAL AGRICULTURIST. 
[AuGiCT 1, 1898. 
which have been fouud iuside the injured grains. 
Although the cultivators say that this molh is always 
present in the granaries, an I do not attach much impor- 
tance tu it, tli.re is no doubt that they do a certain 
proportion of the diiinage. All these iusecta can be 
drivsn out of tho grain, or .ictualiy killed by the same 
metljod of treatment. The recognized treatment in 
America, vfherc most attention has been paid to the 
subject, 18 by means of the bisulphide or carbon, 
evaporated in open dishes on the surface of the grain. 
The vapour formed, being heavier than air, sinks 
through the mass of grain and destroys the insects. 
It is impracticable to uss this remedy in Ceylon, ou 
account of its extremely poisonous nature, and also 
because its importation is dangerous, by reason of its 
great inflammability. 
A simpler and very satisfactory method is the use 
of ordinary naphthalene powder, which can be used 
both to drive out the insect alreaiy present and to 
provent others coinint; in. It is cheip, and there i« 
no danger in its use. It may even be swallowed in 
quantity without injurious effects. Fears have been 
expressed that the germinating powers of the seed 
pafidy may be destroyed or injured by its use, but it 
hxs iieen ti'ied in liurmah without any ill result, and 
there seems no reason to suppo'-e that its use can io 
any wiiy 'ifftct the germiimtidn. 
Consiilermg tlie fact that the beetles are chiefly st 
the bottom of tlu< bins, the best results will bo 
obtained by applying the naphthalene at this level. 
This can be done by the following method, devised by 
Mr, F. W. Cabauiss, Assistant Director of Agricul- 
ture, Burmah (see the " Agricultoral Magazine, " 
Colombo, December, 1897) : — 
" Take a bamboo about IJ in. in diameter and long 
enough to reach from the top to the bottom of the 
bulk of grain. Punch the jo'nts out of tlie bamboo, so 
as to be able to pass a stick through the bamboo, from 
one end to the other. Have the stick made to fit the 
cavity in the bamboo. Pass the bamboo, with the 
stick in it, down through the bulk of grain from the 
top to the bottom. Withdraw the stick and drop 
into the top of the bamboo about half a teaspoon of 
naphthalene powder. The bamboo can then be drawn 
out as the naphthalene is safe at the bottom of the 
bulk of grain. If the bulks are large this should be 
done once to everj' 10 ft. square of the Inilk. Repeat 
the application every fifteen or twenty days as the 
powder evaporates. 
" The weevils that can leave the grain will do so, 
and those that cannot leave are killed by the odour 
of the naphthalene. I do not believe that naphtha- 
lene thus used can cause any injury whatever to 
grain. For seed purpo.'ies the germinating powers 
appear not to be affected in the least. For market- 
able grain the colour is not affected, and the odour 
will leave in a short time if fresh naphthalene is 
not applied to it. The quantity of powder used is 
infinitely small in proportion to the quantity of grain, 
and the powder is entirely destroyed by evaporation, 
so that for food purposes the effect is nil." 
This method has already been tried by several 
Sinhalese proprietors, with satisfactory results. In 
one case that we examined 6 oz. of naphthalene 
had thus been applied to a bin coutfiiniug 530 bushels 
of paddy ; this had apparently driven away all the 
beetles, though only ten days before they had been 
present in very large uumbers. All smell of naphtha- 
lene had disappeared from the paddy by this time. 
This was chiefly due to the fact that tho bin was 
open above to the roof, so that air could freely 
enter from outside. To produce the best results the 
bin should be as closely fitting as possible. This 
will prevent the too rapid evaporation of the naphtha- 
lene, and will also help to keep ont insects. 
In cases where the grain is stored in wickerwork 
baskets, or other receptacles which admit the air 
freely, it will be advisable to render these more 
airtight before applying the naphthalene. This may 
be done by plastering them with cowdnng on the 
outside. 
Spreading the affected grain out in the sun in 
thin layers will also have a very useful effect, by 
killing off the gruba of the beetles before they arrive at 
maturity ; it will also tend to drive away tbe maiare 
beetles and weevils. The same treatment will eu- 
tirely free any grain from the disa^creeable suiell oi 
naphthalene, ii tuch bhould be found haugiug about 
it when rtquiied for use. 
^^ liat has been said above applies chiefly to cases 
where the grain is already affected by the peat , the 
experience of the rava^c^ of these iusrcts should, 
however, make cultivators and deaieis more cureful 
in future to take prevt^utive meaoures against tiie 
repetition of this trouble. A few {euomuieudatiotn 
ou this point will now be given. 
Tightly fitting gransrirs are strongly recoujiuei>d*d 
so as to li^ave aa few apertures a« poaaible (or the 
entry of injurious ius«cls ; a cloi»ely fiitiug buildioc 
is aUo more convenient when remedial uteakUies have 
to be applied. Seed gram might with advantage be 
kept in zinc-lioed bins, such aa are at preaeut ua«d 
in tea fiictoriee. 
Ail refuse grain uhoald be carcfullv deetroyed and 
tho gianaries kept as clean aii possible ; the bins 
should be carefully cleaned out Defore the new grain 
is placed in them, and any reiuainf' of the prexious 
crop should be stored separately. The addition of a 
small quantity of napbthaleue powder to the bottom 
of the bin before the grain is put >n i« strongly re> 
commended. Tho grain should be well diied before 
storing; a> y heating or fermentation is well-kuowB 
to be a pmductive source of weevil. 
Tbe presence of such large numbers of tbe paraai. 
tic Hijinenoiitfia is a very bopefttl sign, and points 
to the probability that the sudden increase of the 
pest has been met by a corresponding increase id tbe 
numbers of these natural enemies, wbicb sboold 
speedily afford a check to any farther extension of 
the injury. E. Eemest Ubeem, 
Honorary Government Entomologist. 
JoH> C. Wu.LH, 
Director, Koyal Botanic Oardena. 
RUBBEi;. 
There are four different species of rubber-producing 
plants growing in tbe station. The most common 
species are the native rubbers (Landolphia oirarirniU 
and L. Horida). These abound on the Gambia, but 
owing to the rathlesn manner in which the trees are 
tapped, it is feared they will soon disappear. 
Uetca brasiliensis (Para rubber). — A few plants of this 
are at the station, but they do not appear to be growing 
very well, owing to the long dry season. 
Cdffilloa elastica (Central American robber). — 
Several plants were brought out by me e.s already 
mentioned from iew. They are now growing well, 
and are about two feet high. These plants are said 
to grow well in a deep warm soil, composed of loam 
and sandy clay ; a dry or rainy climate seems equallv 
suitable, but a high and equal temperature, whicb 
does not sink below 60° F. at any time is essential. 
ilanihot Glaziorii yields the rubber known in 
commerce by the name of Ceara rubber. This plant 
grows well in the Colony. The only difl&culty up to 
the present has been to procure the rubber from tbe 
tree. The sample of rubber collected from a tree 
growing at the station is free from impurity, but, 
though small, it is quite large enough to ebowth&t tbe 
method of collecting I have practised is the correct 
one and the one which slionfd be impressed on the 
local rubber collectors. The plant is very hardy, and 
will grow almost anywhere. Its heathy appearance 
in this Colony shows that it may prove of great value. 
— Kew JJuUetiii, 
Coconut -vxd Tobacco Planti.vg is thk 
Trincomalee District forms the subject of a 
communication elsewliere from a resident who 
gives a good ileal of information about the 
land.s available. We fear the Trincomalee dis- 
trict is, like Jaffna, too dry for coconuts; but 
alluvial land ou the banks of the rivers or near 
backwaters ought to be well suited for the palm 
and certainly water-carriage is an attraction. 
