, 1894-05-30
REPORT ON DISEASES AFFECTING TIE
SUGAR-CANE IN BARBADOS.
COnti red from Avis No. II.
By C. A. Barber J

'NA NAAAN wv ''@
iect Of my enquiries is a much less tangible
affair. As already stated, Mr.. Bowel sent a
batch of diseased stools to Kew and Mr.
Massee determ. ed the fungus to be ColletO-
trichN. a. alcatum, q species recently described
as %injuring the fields in Java.
The disease appears to be fairly local i'll its
distribution, being almost confined to the
higher, red soils Of St. Johns parish. |
visited the typical district. The general
effect Of this disease is that the canes planted
in December appear 20 receive a check in
their growth about June or July following
As time proceeds the plant gradually dwin-
dies. al hough many attempts are made by
fresh basal shoots to supply the place of
dying ones. After the lapse Of six months
i g., III November aud December. ITO cane
has been formed, growth having apparently
been completely arrested. Upon digging a
plant up out Of the soil, one is struck by the
mass Of old, dead Ioots-the healthy young
ones being few in number.
This disease again .ho%s a marked prefer
ence for Bourbon canes. They are much more
frequently and severely attacked than the
other varieties. such as CaIedonionIQueen Strip
ed Singapore. Purple Transparent, which are
met with in the fields.
The field examined, and from which |
obtained my specimens. consisted of Bour-
ions, supplied here and there with striped
and purple canes, and divided by two broad
bands Of Caledonian Queens. The latter
were, it is true, Of no great size, but they
we're arrowing freely and the difference be-
tween them and the Bourbon was marked
enough, while all supplies were at once seen
to be comparatively healthy. l collected
typical specimens of all parts of the Bourbon
and Caledonian Queens and placed them in
alcohol upon the spot. The loss on the es-
tate visited may perhaps reach 75oio or 8OoIo
of the crop.
The attacked canes appear to have fairly
healthy tissues, in no way remarkably red
in colour as might be expected. l have exc
amined three lots from different places hav-
ing cut sections through young roots, old
roots, all parts Of the shoot, young leaves,
and old leaves. My examination was per
force cursory, but in no case did | succeed
in finding any hyphae in the living or fresh
I tissues.
J l found a thick, ropey mycelium in the
earth around the roots, similar to that in
the diseased pine apples ut COpse Cross IN
Antigua. Hyphae were seen in the cOrtex If
old roots, while no traces were observable
inside the endodermis old, dead leaves had
hyphae connected with the black star-like
spots on the surface, consisting Of conidia III
the midst of radiating black hairs. | saw
no reason to suppose that the. hyphae men
toned had in any way caused the death of the
parts affected. but it occurred to me that they
were saprophytic. They occur with equal
frequency upon the Lealthy observation-disclosures
near by and elsewhere, and also in great guam
titles On the dead leaves Of healthy Bourbon
canes wherever | have examined them. |
did not find any fungus in the tissues Of
dying leaves.
From the foregoing it will be gathered
that 1 did not succeed in finding any fungus
to which l could refer the disease. / sab.
mitted the slides to Messrs. Bowel and
Albuquerque, and they likewise failed to
detect any hyphae. Now cells destroyed
by fungi are usually permeated in all direc-
tons by their byphae. The specimens for
ward 1 by Mr.. Bovell to Kew were, | sup
pose, pulled about nine weeks before my visit,
but see no reason why the hyphae should not
remain in the plants.
From these considerations and the general
appearance of the plants, | recommended the
Of series of sections through the deli
cate root tips and other parts of diseased
plants. and staining for bacteria,-a course
which Professor d~'Albnquerque agreed to pur-
sue. | shall await his results with interest.
The presence of bacteria in plant tissues, |
NAV point out, is not necessarily a sign OF