Evening star. [volume] (Washington, D.C.) 1854-1972, 1930-07-31
DIRECTOR Of FARM
.SOLVESFLYM
|. AT ST. EL|zABETH'S
DIGS Trenches Around Fer
tiIizer Heaps and Pours
in Crankcase Oil.
METHOD KILLS LARVAE
IN THIRD STAGE OF LIFE
City Health Departments Are
Showing Interest in New
Discovery.

st. Elizabeth's Hospital has been al
most rid of flies with method devised
by D. A. Brodie, farm superintendent,
which may have a worldwide applica-
ton.
This consists simply in digging foot
deep trenches about the fertilizer heaps
on the 400-acre farm and pouring into
them approximately a three-inch layer
of drained crank-case oil. The same
method could be applied with almost
no expense in farm yards and on the
grounds of other institutions.
1t has been we'll known for years that
flies lay their eggs in fertilizer heaps,
where they hatch into worm-like larvae.
Hitherto efforts have been concentrated
on the heaps themselves. Various chem
ical treatments have been devised which
kill the larvae effectively enough. All OF
them, however, have decidedly affected
the value of the fertilizer, and farmers
have been loath to use them.
Studies Life Cycle.
Hundreds of millions of flies used to
arise from the farm and invade the
hospital grounds every Summer and
even the best-grade screens could not
bar them entirely from the wards and
kitchens. When the problem was put
up to Mr.. Brodie he studied the fly's
life cycle and found that the larvae in
variably crawled from the fertilizer
piles and burrowed into the soil nearby,
where they underwent the third stage
in the life of flies, pupation. Here they
were wingless and helpless.
Then Brodie remembered his expert
ence with a cut worm invasion 20 years
ago, when he was superintendent of an
agricultural experiment station in
Washington. The vast army of insects
advancing along q 2-mile front, had
been stopped by digging trenches, up
whose perpendicular sides they could
not climb. They reminded him of the
advancing hordes of fly larvae. The
only difference was that If the larvae
waited in the trench thrown in the
path of their advance out the fertilizer
pile and into which they were bound
to fall, in few days they would get
wings and ny out.
Oil Solves Problem.
The problem was to kill them before
they grew wings. The drained crank
case oil was going to waste. and he
tried 1t as an inSecticide. The results
exceeded all expectations. Morning
after morning all Summer farm work.
men have scooped of the surface OF
the oil shovelful after shovelful Of dead
wormlike forms-fiieS in the second
stage of their life cycle. As a pile is
enlarged the trench system Is enlarged
to surround it. The only flies who es-
cape are a few sIow-moving larvae who
are overtaken by the pupation stage on
their way out of the fertilizer pile, and
these probably do not include one In q
million. AS soon as the larvae are
Matched they seem to move automatical-
ly, obeying mysterious urge of ma
ture, to get to dry place to spend the
helpless days Of pupation.
The method has not entirely rid the
hospital grounds Of flies. but on the
first of August, the height of the ny
season, there are no more than would
be there normally the first Of April.
Fly swatters have become nearly use
less implements. Fly traps still are
used about the diaries. For the first
time members of the staff can dine on
tables set on the lawn outide the cafe
terra in comfort. The physician In
charge of one building said that he has
not had l per cent of the flies this
Summer as in other years, and stated
seriously that he believed the farm
superintendent has made one Of the
most notable scientific discoveries In
the history Of the hospital. The entire
residential section around the hospital
is feeling the change.
Interest Shown In Discovery.
The method cannot be expected TO
eliminate all flies, Mr.. Brodie said, be-
cause they lay eggs IN millions Of places,
but 1t can almost entirely check them
at the source of the greatest numbers.
City health departments already are
showing an interest in the discovery.
One application, Brodie said, will be
on farms where flies. Matching in the
untrenched fertilizer piles in the BARN
yards, have everywhere been an uner-
radicable pest. Probably the great
majority of the flies which affiict cities
come from a comparatively few con-
centration points
1.-THE TRENCH Mr.. Brodie said, soften
has been used to check insect invasions,
but, so far as can find, nobody be-
fore ever has thought of using it
against flies. With us it was simply
case of necessity being the mother of
invention. The fertilizer was essential
for running the farm, but either the
fertilizer or the flies had to go. BY
striking at the fly in the pupation stage
we had the insect when it was defense
less. Folks have been swatting. poison
ing and trapping flies all over the world
for centuries, but they have attacked
the ny at the stage where 1t was best
equipped to fight back"