The Florida agriculturist. [volume] (DeLand, Fla.) 1878-1911, 1897-06-02
the plants. but has only slightly checked

the plants, but has only slightly checked
their spread.
Utilization of the Water Hyacinth.-As
mentioned above, the water hyacinth is
good food for cattle and hogs, and hun
dreds of those animals may be seen along
the shores of the st. Johns in the win
ter grazing on the weed. The plant has
been used to some extent for a fertilizer,
being put on both when rotted and while
green. With some garden crops, such as
potatoes and cabbage it is said to have
given excellent results The fertilizing
properties of the plant must, however,
be comparatively small, as a large per-
centage of it is air and water. However,
the various uses to which the plant may
be put cannot be expected to involve it's
destruction to a sufficient extent to aid
materially in keeping it under control.
Probable Effect of Diseases.-From
what has been said, it appears that the
eradication of the water hyacinth by me
chanical means is practically impossible,
and that the use of dredges and other
mechanical devices will simply result in
keeping the plant in control at cOntinu-
Gus expense. There is, however, another
means of combating pests of this nature.
namely, the introduction and spread of
their natural enemies, which, in some in
stances, has proved thoroughly effectlve
canadensis, Michx., Britton), which,
when first introduced into Europe, caus-
ed very serious trouble in canals and r1v-
erS and then gradually disappeared is
male plants of the water weed were in
troduced into Ireland in 1886, into Great
Britain in 1841, and later into many rivers
and canals in Middle, Southern, and
Northern Europe. The weed multiplied
rapidly, and soon became very trouble
some to navigation and fisheries in many
canals and streams. After a number OF
years it became less abundant, reproduc-
ing less rapidly, and gradually decreas-
ing in most places until it no longer
causes serious trouble. Many authorities
attribute this decreased reproduction to
the effect of natural enemies, which have
multiplied until they keep the pest under
control The water weed roots in the
muddy bottoms of rivers and canals, and
some authorities attribute the decreased
numbers of the plant to the exhaustion
in the soil of the specific nutriment on
which the plant feeds. The water hya-
cinth, however, is a floating plant, hay
ing commonly no connection with the
soil, and therefore could not be affected
in this way.
The introduction of the lime tree (citrus
limetta) on some of the Florida keys fur
nishes an illustration of similar nature.
If the lime is introduced entirely free
from it's natural enemies it grows rapidly
and thrives without culture. If, however,
a single enemy of the lime for instance,
the purple scale insect (Mytilaspis citri-
cola), be introduced, the trees will be
killed to the ground, if not killed out en-
tirely. If, however, when the purple
scale is introduced, it's fungus and in
Florida keep the pest in control, are also
introduced the scale will probably not be
allowed to increase rapidly enough to Sc
riOusly injure the lime.
An Enemy Discovered.-Th writer has
made a careful search in Florida for dis
eases which may prove of Importance in
combating the water hyacinth, and has
discovered one leafspot malady which is
widely distributed and unquestionably
damages the plant considerably. This
disease is caused by a parasitic fungus
which attacks the leaves in spots, form
ing concentric circles and ultimately
kills the entire leaf. 1t is highly import
ant in the writer's opinion, that a care
full search be made in the native home of
the plant for additional diseases which
may be introduced here to aid in keep
ing the pest under control. Although it is
by no means certain that any exceeding
ly virulent diseases would be found, yet
many minor maladies would doubtless be.
discovered which would aid in control
ing the weed. The introduction of the
natural enemies of the plant, together
with the remodeling of the bridges in or
der to allow the river current to carry as
much of the material out to sea as pos
sible, wuold probably keep the pest down
so that it would not seriously ObStruct
nevigation This would necessitate but
small initial expense, and, if successful,
would permanently solve the question:
Washington correspondent Citizen.