Evening star., 1939-07-16
Pest Likely
TOPrOduce
ManyEvils
Navigation, Health
And Wild Fowl
Need Effort
By Joseph S. Edgerfon.

Of Columbia and downstream into
choked morasses of matted vegeta-
ton, which drive away wild fowl
and fish, close the shallow waters
and tributaries to bathers, boaters
and fishermen, and which are
threatening to create plague of
malarial and other mosquitoes and
menace the health of local residents.
Faced with a problem of even
more serious consequences than that
created by the water hyacinth
plague of Southern waters, the local
Army engineer Office, headed by Col.
r. S. Thomas, now Is launching
fight to control the new pest, the
water chestnut.
Unless funds are appropriated and
an organized campaign is under
taken over period of perhaps 10
years, however, there is said to be
little hope of eradicating a pest
which, if unchecked, may eventu-
ally destroy the Potomac as recrea-
tional area and convert it into a
source of pollution and disease.
First noticed in the Potomac River
In 1928 or 1924, the water chestnut
now infests areas along both shores
of the Potomac River and its tribu-
tarles from Columbia Island to the
mouth of Aqua Creek, not far
above the upper limit of brackish
water, into which the plant cannot
penetrate.
Clear Away Growths.
The Army engineers, under Col.
Thomas, now are carrying on an
intensive program of experimental
work to determine the best methods
of controlling and eradicating the
plant. Their efforts, with the aid
of the Civilian Conservation Corps,
the Biological Survey of the Agri-
culture Department and local or
ganizations, have resulted in clear
ing away the unWholesome, de-
structive growths from their present
upper limit at Columbia Island to
OXon Run, opposite Alexandria, Va.
The last remaining patches of the
plant in the Washington Airport
yacht basin at the lower end of
Boundary Channel now are being
attacked. The Reaches Run Wild
fowl sanctuary, in which C.. C. G.
enrollees fought the chestnut men,
ace last year, also has been cleared.
OXon Run, however, is heavily in
Tested and has been converted into
test area, in which the engineers are
employing poison spray, underwater
mowers and a powerful gang saw
machine to develop suitable tech
nique for employment in a thorough
campaign of eradication, if funds are
made available.
Acres of solidly massed water
chestnuts. however, are growing un-
checked along 81 miles of the Poto-
mac River and into its tributaries,
developing thousands upon thou
sands Of sharply -pronged, hard seed
nuts to be carried into yet unin-
fected areas and to wash into bath
ing beach areas to puncture and
tear the feet of unwary bathers.
Long Known Abroad.
Little is known of the earlier eX-
istence of the water chestnut, also
known as the Caltrop and Bull Nut,
except that in Europe and Asia it has
been known since early times, ac-
cording to report prepared by
the Army Engineers. In Asia the
nuts are reported as being used for
food, medicine and magic. At pres
ent the plant in Europe appears to
be dying out, but whether due to
attack of disease or other causes is
not known. In earlier geological
periods a related species grew in
America from Alaska to Alabama
but this type is not found today.
Evidence indicates that the seed
of the water chestnut was first
brought to America from Europe in
about 1884 as curiosity and that it
secured its first foothold in the Mo-
hawk River in Eastern New York"
according to the Army report. 1T
was first noticed about 1923 or 1924
in the Potomac River at the mouth
of Oxon Run, opposite Alexandria,
Va, 5 miles downstream of Wash
ington. Since that date it has spread
downstream from Alexandria about
81 miles to Aqua Greek, the upper
limits of definitely brackish water,
and has spread upstream miles to
Washington, where it is now firmly
established in the small boat harbor
at Washington Airport.
Nearly all coves and tributaries
of the Potomac, as we'll as many OF
the shoal sections of the river, are
completely or partially chicken dur
ing the summer season by the water
chestnut plants. The area infested
in 1888 in the Potomac Basin is ehtl-
mated at 1000 to 10000 acres"
The water chestnut, botanically
known as the Trapa natans, is an
annual water plant growing in fresh
water only. Tile burrlike seed ger
inmates about april l in this area
In the mucklike bed of the river, and
thin, cordlike stems grow to the
surface of the water, where rosettes
of leaves are formed. The stems of
the plant may reach a length of
ID or Is feet, with four to nine
branches, each with a dense cluster
of leaves. The roSettes range from
IL to 18 inches in diameter, and the
leaves composing them are glossy
and leathery, about 11a to inches
in diameter.
Tensile Strength.
SpOngy, DuOydnI DulpS al une DaSe
of the leaf stems support the leaves
on the water surface. Small flow
ers are borne on the aXil of the
leaf. from which develops the seed,
which gives the plant its popular
name. AS many as Is to l8 of these
water chestnuts, or seed-nuts, are
produced by single rosette, or a
total of so or more nuts on some
plants. The soft, vinelike stems are
smaller than lead pencil but are
said to have tensile strength equal
to that of common, grocery-store
twine.
The density of the foliage is esti-
mated at about 20 pounds per square
yard of water surface at the peak
of its growth. The plant, although