, 1913-03-05

upon all exposed surfaces. In order for a
~spore to grow into a mature fungus, certain
conditions are necessary. One condition is
that the surface must be damp, and another
is that it must be composed of the right
material. The spores Of different fungi re-
quire different materials. Some fungi are
very particular and can only live on one very
special kind OF material. Arrived on the
right kind of material the spore 'absorbs
water and swells and then protrudeS a tiny
tube at one or more points on It's surface.
The tube penetrates into the substance Of
its host, absorbing nourlshment from 1t all
the time, and it grows into % delicate thread
which branches and ramities all through the
material on which it feeds. The delicate
threads of which a fungus is composed ure
called 'hyphB" and the mass of
threads is called the "mycelium" of the
fungus. After o time the fungus produces
special bodies called fructiticulIonS" and
these qualifications bear spores. The fructlti-
cations are generally formed on tAe exposed
surface Of the host mate lal and the spores
are shed and carried away by wind There
are several parasitic fungi attacking cane
plants in this island but the one which does
most damage is the Root Fungus-Wurds-
9nius .SQcchari. We do not know detini ely
that this fungus lives on anything but sugar
cane. Similar fungi are found on grass
roots, but they have not been proved to be
identical with the fungus found on canes.
Canes attacked by root disease look as if
suffering from drought-the leaves begin to
dry up at an early stage, the tip and edges
first becoming brown and dry. Then the
old dry leaves at the base OF the plant will
be found not to drop off leaving " clean
stem as they should do, but they remain
attached firmly and resist being removed.
When torn off, the inner surface OF the leaf
sheath and the outer surface OF the cane is
found covered with a white, musty-slnelling
stuff; this is the "mycelium" OF the fungus.
n ,ther the small roots which may be spring
ing from the nodes of the cane look unheal-
thy-and are red or black at the tip. In
wet weather there may be found bursting
through the diseased leaf sheaths of the cane
small toadstoolA. These are the fructifca-
lions of the fungus and they produce the
spores. When all the leaves of the plant
are withered up, the cane itself will be found
ON splitting it open to present a characters
tic appearance. | pass round specimens
showing the disease in different stages.
The Root Fungus disease is always worst
III a dry season because 1t is more saprophy-
tic than parasitic in habit 1t is q saprophyte
10y choice, you may say, and a parasite 10y
necessity. When q cane is i'll a weakened
state by reason of drought then q fungus
rapidly tonquers. In good weather it makes
little progress but simply bides its chance,
and as soon as drought weakeDs the vitality
of the plant it seizes the opportunity and
starts to kill the cane.
How does the Root Fungus spread We
have seen that the fungus produces fructi-
4cutions and spores, but this is only n minor
way of spreading in the case Of this fungus.
The qualifications are not numerous except
in very damp weather and this We seldom get
in St. Croix. The chief ways i'll which the
disease is spread in this island are as follows:
l. By the use Of diseased material for
planting.
2. BY the presence in the soil of pieces
of old cane etumps and roots, all full of the
mycelium of the fungus.
This being the case the remedies are OBJ
Vious.
First and foremost use for planting pur-
poses the soandest and best cane on the
Estate.
The present practice of using a turned out
End or 3rd ration piece, which IS nearly al
wnys full of disease, is a suicidal policy. l
suggest for the serious consideration OF
the Planters that they might rent land on