Evening star., 1939-07-16

sinks to the bottom. This seed is
of peculiar shape, about the size
of a walnut, having a hard, irreg-
ular, bonelike shell with four pro-
truding barbs or horns, which are
sharp and thornlike. 1t is similar
in shape to the military obstacle
of the ancient Greeks known as
the caltrop, from which it gets
one of the names by which it is
known. The nut or kernel is one
half to three-fourths of an inch
in diameter and is said to be pala-
table and rich in food value. The
hard covering with its horns or
barbs prevents its use by birds and
fish for food.
Danger of Disease.
Use of the nuts for human food,
however, may be dangerous in this
vicinity, as the plant thrives best
where the water is dirty and polluted,
as result of which disease may be
contracted from eating the nuts.
The adverse effects of the water
chestnut growth in the Potomac so
far is felt principally by owners of
pleasure craft, since there is little
commercial traffic on the tributaries
affected. Because of the heavy
growth, many of the creeks and
coves formerly used by small boats
and sailing craft no longer can be
used during the summer season,
thus seriously restricting recreational
activities in the upper Potomac.
There is not suitable protected
anchorage within few hours run Of
Washington which is not at least
partially infested" the Army en-
gineers reported. These areas have
been a rendezvous for week end
cruises which are popular with the
large yachting fraternity of the Ma
tion's Capital. In addition, there are
long reaches in the shoal areas of
the main Potomac which cannot be
used by small craft. Pleasure boating
of the many shore owners is seriously
handicapped. The use of rowboats
and skiffs for general recreation,
hunting and fishing in any infested
area is virtually impossible at the
height of the growing season"
In August, when the plant is dis
integrating, large mats of the leaves
drift out into the channels and form
serious distractions to small craft,
fouling propellers. A report from the
Capital Yacht Club emphasizes the
urgent ned for measures to eradicate
this marine pest.
"At the rate the growth has been
increasing the last few years." the
club reported, "it will not be long
before the Potomac River itself will
become so obstructed with it that
navigation will be almost impossi-
ble."
Affects Water Fowl.
One OF the most serious effects of
the water chestnut infestation is the
destruction of feeding grounds for
water fowl The thick mat of leaves
shuts out sunlight essential for the
growth of wild rice and other vegeta-
ton on which water fowl feed.
This is now true of most of the
extensive wild fowl feeding grounds
in the fresh-water sections of the
Potomac tidewater, and ducks and
geese are no longer coming to this
section in large numbers" according
to the engineer report.
The Biological Survey of the Agri-
culture Department, which at one
time listed the Potomac as an i'm
portant water fowl feeding ground,
because of the water chestnut in
festation no longer lists the local
waters as a haven for water fowl.
The thick matted growth also has
destroyed the native species of vege-
tation which supports the life that
forms an essential food for game fish.
Many sections of the river are almost
completely devoid Of any plant life
other than the water chestnut. Coves
and tributaries of the Potomac River
formerly well known for game fish
ing. according to the Izaak Walton
League, now produce very few fish
which may be caught from small
boats.
The thick beds of water chestnut
collect large quantities of organic
waste and create pollution hazards.
This matter decomposes under the
hot sumner sun, with a resulting
stencil and unhealthful conditions.
and In the comparatively stagnant
water in the plant beds the mosquito
breeds prolifically.
Arsenic From Planes.
To control the malaria mosquito,
the United States Marine Corps at
Quantico dusts the water chestnut
beds in the vicinity with arsenic
from airplanes at Today intervals
from July l until frost in the fall.
Complaints have been received from
other localities along the river that
the water chestnut beds are causing
a marked increase in the mosquito
nuisance.
Col. S. w. French, Army Medical
Corps, until recently on duty at Fort
Washington, Md, reported that from
the standpoint of public health the