The Daily bulletin. [volume] (Honolulu [Hawaii]) 1882-1895, 1891-10-24
DISEASED BANANA PLANTS.

The secretary of the Agricultural
and Industrial Association OF FIJI
communic,a with the Department
of Agriculture under date of June l6
last, notifying the despatch of a case
of diseased banana plants, and ask
ing the Department to interest itself
in having the disease thoroughly
investigated. From this letter 1t
appears that the disease has dehed
eradication by the banana planters
of Fiji. The facts seem to snow
that it affects the young plants; that
after they are set and begin to grow
the outer leaves begin to turn
brown, drop, and die; and that the
succeeding leaves do the same as
they reach from Ain. to = in length.
The plant continues growing IN this
way for several years without much
increase in size, instead OF growing,
as it should, to height of from Git.
to lift. and producing fruit. The
disease is said to be very serious, al
though sufficient information has
not yet been furnished to indicate
the exact extent OF loss.
In connection with the matter it
may be mentioned that the Depart
ment also received from the Clar-
ence River some six months ago
- 1IonacnI
as this specimen consisted of grown
plant after it had been cut down it
was not possible TO make out very
much. Apparently, however, this
disease from FIJI is the same as that
sent from the Clarence, and mas
much as the Government Patholo-
| oist has been able to find out a
number of causes for the diseased
condition of the FIJI plants, reason
exists for making them known, as
that information may be of assist
ance to the banana growers in the
northern part of this colony. The
Fiji plants were found to be in
some parts covered with amphides,
or plant lice, and these were so
numerous on some of the plants that
they might have done considerable
damage. Still it could not be
proved from examination that they
had done much damage, although
they existed in very large numbers
as many as several hundred cast
off skins being often seen in the aXil
of one leaf. The Government En-
tomologist, who has made an examin-
alton of those aphl1es believes them
to be a new species. In the root
stock of the FIJI plants fungus
was found. What the exact nature
of the fungus is, has not yet been
ascertained, as no spores could be
found. The exact systematic posi-
ton of the fungus remains unknown.
But the fact that it does a great deal
Of damage has been established. Its
presence may be known by brown
discoloration of the interior of the
root-stocks and roots. The tissues,
instead of being white, as they are
when healthy, take on where the
fungus is thickest dark brown tint,
and where it is just penetrating and
has not yet caused serious destruc-
ton of tissues, light brown color.
1t is rather remarkable that in the
soil about the roots of those plants
nearly thirty species of nematodes
should be found, about 20 of which
are new species. Two of those
species have been shown to be in
furious to plants one of them attack
ing the roots, and being found living
parasitically on certain brown rotten
cavities, and the other being founo
between the sheaths of the plant
and in some cases even at the very
core, where the tissues appeared te
be quite sound and white. 1t will
therefore be seen that there are foul
distinct and separate causes for the
diseased condition of these plants
viz, aphides or plant lice, fungus
causing rot in the root-stock, anC
two different species of nematodes
The remedies that are suggested
in the present state of our know
ledge, which, of course, is incom
plete, are these:-1. That where
the bananas are cultivated system
of rotation should be adopted; tina
: no attempt should be made to grow
the banana plants on the same lane
continuously for a long series 0
years, and this for two reasons. Il
the first place, the soil naturally be
comes exhausted of the element
necessary for the growth of tn
banana plants, and therefore afte
series Of years the plants becom
weakly, and do not thrive as a
first. Furthermore-and this
quite as important as the first reason
in the opinion of the pathologist
if the banana plant, or any othe
plant for that matter, is grown con
tinously on the same land for
! long series of years, the diseases o
| the plant are bound to accumulat
on that piece of land. The disease
which first appears in mild form
and only here and there, will i
each succeeding year attack NOR
and more plants, and usually in
more virulent manner. Unles
special precautions are taken t