, 1892-05-04

~N~ NAS 'NS w. A@AOAyt a ~ ~
a cane that has not previously bean ravsged
by the moth-borer. This may easily be seen
by close inspection, and to note how far this
theory held good, | have repeatedly taken
specimens at random from various parts. of an
affected field, and have always found that IN
the majority Of whithered and diseased-Iooking
canes. there were the large tracks Of moth-borer
without q trace Of the beetle in a great many
instances, there were the tracks of both moth
borer and beetle in the same cane, but never an
l~nstaAce of The beetle alone. Mr.. Grant, the
manag er of Woodlands estate in this island
has been with me at several of these investlga.
TONS, and after examining numbers Of specl-
mems, we are pretty well convinced. as far az 1t
affects Gienada--that not only does the moth
borer first attack the cane, but that the beetle
never commences its work until the care has
become thoroughly soured and the following
appears TO be thesreal history of the disease.
There is a moth (Dtatraea SacchdrGlis) very
commonly to be seen fitting about the cane
fields in all these islands. This moth is about
one inch or more across the wings, which are
of q light silvery grey colour. The female
moth lays her eggs in the cane, at q younger
stage OF it's growth, near the axil of q Ieatblads;
the larva, when Matched, makes it's entry into
the stalk, generally near a joint, and having
reached she soft pith inside, commences to tun-
mel through it. The growth OF the insect at
this (larva) stage is very rapid, and its appe-
tite enormous. 1t remains in this state for
about 80 DAYS, and when full-grown Is q wotm-
like creature about one inch long, rather slend-
er, and of a cream white color with a yellow
head and darker mouth parts. When q full
grown larva. it bores to the outside of the cane
and makes q large round hole for it's exit. We
frequently see this hole which is about 9Th of
an inch in diameter, in one If the internodes
or spaces between two Joints. Having provld-
ed for it's future exit. it goes back into the
cane, and becomes transformed into q brown
pupa. In this stage it remains quiescent fer q
few days. and then the perie Q moth energies.
At first the cane shews no sign of the moth
borer that is working within, and for sometime
remains vigorous. Hence planters naturally
nevor think that anything is wrong, But al
ter time, when the inside is thoroughly ravag-
ed and the circulation Interrupted, the cane
shews signs Of whitening, and their attention ia
then directed to it. At this stage the cane will
be found to be quite sour, aud to have acquired
a distinct acid smell.
Here the part of the beetles comes IN. At
tracted by the sour stuff, their natural food, they
flock in great numbers to the diseased canes,
the females make their entry, lay their eggs.
these hatch, and the larvae, which aye small
thread-like insects about 9Th Of an inch long,
mmen their ramifcations. Thus they may
DO found in all stages of this growth, in a cane
from the larva to the perfect insect.
1t rarely happens at this season Of the year,
and also in really sour canes, that the moth
borer is to be found at work, for tbs reason that
Il has already emerged as a perfect insect but
when a diseased cane is examined, it is often
found full of beetles al work within, and the
general conclusion is that the beetls is the dsS-
troyer, whereas, if closely examined, the Largo
er tracks Of the moth -borer will always bs
found.
! am therefore Of opinion that We must frat
endeavour TO eradicate the moth pest, and, hav-
Jug done that, l feel sure that the beetles will
give little trouble to sound canes. AS a re-
nelly l would suggest the advisability IF cut
ting the ripe canes as quickly rs possible.
Take up every piece of rotten cane carry them
out of the field and pass them through the mill
this will destroy any g ubs that may chance
to be in them. Burn all the megass, for a couple
of seasons at least, as the method Of stacking
megass for future use may assist in keeping up
the disease on no account leave pieces Of rot
ten cane lying around the estate, these only
form breeding ground for fresh hordes of in
sect pest. The trash and stumps should then
be collected, oarted away from the field, and
burnt. Tho reason OF this is, that in some
places it has been found hat there are help ants