The Hawaiian gazette., 1904-04-08

injurious insects, i'll which case infection
OF the cane with the fungus occurs
through the wounds made by the insects
Whenever young plant cane looks yell
low and sickly or when seed cane fails
to gcrminate, or when growing cane
shows retarded growth and has its
leaves and stalks streaked with red
patches. or when dead cane either stand
ing in the fields or that which is left
OH the field after the crop has been
harvested appears light and spongy and
is covered with small pustules or bis
ters, the patches of cane exhibiting any
or all OF these symptoms should be look
ed on with suspicion: Under no cir
cumstances, should seed cane be taken
from such fields.
THE BROWN-EYED DISEASE OF
COFFEE.
A fungus-disease of coffee, causing
spotting of the leaves and injury to the
berry, is widely prevalent, although
rarely destructive, i'll the Hawaiian
coffee plantations. This fungus has
been identified by Mrs. +. w. Patter-
son, Mycologist of the u. S. Depart
ment OF Agriculture at Washington, ID.
C., as Cercospora coffeicola B. & c. Its
presence i'll Hawaii was noted as early
as 1896 or 1907 by Prof. A. Koebele, the
well known entomologist. In January,
1900, Prof. Koebele reported this fun
gus as causing some losses in Puma and
Olaa. He says: In the wet or cooler
parts OF Puma and Olaa the disease
seems to spread, As yet it is only Sc
rious to weak trees or nursery plants
where exposed, but is hardly noticeable
on healthy and vigorous trees" Its
presence on coffee trees has been noted
during the past three years in all the
coffee districts which the writer has visit
ed As Professor Koebele points out in
his letter in which he first drew the
attention of our Department to the oc-
curence of this fungus disease in Ha-
waii, 1t is most prevalent on weak trees,
such as those i'll neglected and uncarcd
Tor plantations, or on isolated trees
growing in unfavorable localities, such
as door-yards, washed ridges. barren
and rocky, shallow soils.
The Brown disease has been re-
ported from Jamaica, Guatemala, Gaude-
loupe and from Brazil, in the latter coun-
try being widely distributed through all
OF the cottee-growing provinces. Noack,
who has studied the life history of this
fungus in Brazil, describes it as follows
The disease produced by this fungus is
called the Brown-eyed disease on ac-
count of the brown spots formed on the
leaves. As a rule these are round or
oval, on the lower surface clear brown,
on the upper surface dark brown. In
the center the spots are lighter and
grayish. The margin is sharply defined
on the i,pnpr cprfnca Il, FL lrn,,,, n,- col
dish, generally slightly raised, the sur
face often marked by fine concentric
striae. Frequently several spots unite.
The nerves of the leaves do not prevent
their spreading. The average diameter
of the spots at the center of the leaf is
one-tifth of an inch. The largest are
about one-third of an inch. If leaf is
badly affected it appears more or less
brown The formation of the spots be-
gins on the upper surface of the leaves.
The spots are at first without a sharp
line and are scarcely visible on
the under surface. The fungus not only
occurs on the leaves but on the half
formed cherry. On these, little dark
spots appear, which multiply and spread
until finally about half the cherry be-
comes brown and dried"
Many of the cherries which are in
fected with this disease drop off Those
which remain on the tree do not ripen
well and the beans become black, besides
being incompletely developed. Even in
mlder attacks where the above serious
condition does not prevail and the bean
remains uninjured great difficulty is met
in properly hulling the infected berries.
The minute spores of the fungus may
be blown about by the wind or carried
from one plant to. another on the bodies
of insects. Infection has been shown to
occur only when the epidermis of the
leaf is punctured by insects such as the
aphis and torpedo fly (Siphanta acuta)
Treatment to prevent serious losses
from this fungus disease would naturally
come under two heads, first, improving
the general condition of the coffee by
better tilage of the soil and the use of
the proper fertilizers; second, where
many trees are seriously affected and il
is desirable to prevent the spread of the
fungus through the plantation, by the
use of fungicidal sprays or washes.
So far as recorded in the literature
relating to the Brown-eyed disease of
coffee no actual experiments with con-
trolling II by the use OF fungicides have
been made Similar diseases of other
plants have, however, been successfully
by the use of Bordeaux mix
lure and the ammoniacal solution OF
copper carbonate Fungi OF the genus
Cercospora are the cause OF diseases OF
celery, plum, sugar beet and mignonette !
In each Of these cases one or the other
IF the above remedies have proved
BY analogy it is perfectly safe
10 recommend the use Of fungicides, The
ime OF application and strength OF solu-
ion required will, however, have 10 be
worked oul by the individual planter 10
,ut local conditions Both iunglcides
must hc lnuled hy means oi spray
lump bon lhe same manner 40 lnsecl
'ldus
llur description ni lhr various forms
II spraying devices ssc hul M. g NJ
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Hawaii
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