Evening star., 1942-05-28

Federal park officials were spill
ing no military secrets t>lay IN
disclosing precautionary measures
taken to repel an army Of "grubby
little Japs" now known to be hatch
ing a June invasion Of Washington's
choicest grass-covered public areas.
They had reference, Of course, to
the japanese beetle which, like It's
human Nipponese counterpart, in
vades foreign soil to live of the
fat Of the land.
The war against the japanese
beetle has progressed so effectively
since 1910. however, that the Ma
tional Capital Parks once believes
the once dreaded breed faces
early determination in Washington.
We've got the beetles on the run
in most areas and we've certainly
got them licked on the Anacostia
and East Potomac golf courses"
Alton E. Rabbit, assistant agrono-
mist, declared.
Defense Began In Fall.
The present pleasing appearance
Of the park lawns in downtown
Washington, notably in the Mall,
Potomac Park and the Monument
Grounds, is not due solely to the
successful campaign to eradicate
the japanese beetle. That helped
a lot. But park ofacials said that
what helped more was better
grade of grass seed and q plentiful
supply of new fertilizer with q high
nitrogen content.
Precautionary measures against
the expected beetle invasion next
month were taken as far back as
fall. Spot spraying of park lawns,
where the grubs or larvae breed
during the winter and spring, kills
the bulk Of them.
The female beetle lays between
80 and 40 eggs in the soil at depths
of two to six inches. And there
are countless thousands Of females.
During April the grubs move near
er the surface and feed on the
roots OF the grass. Early in June
they begin to emerge as adult beetles
and by mid-July they come out in
force. That is, the ones that sur
vive the spraying come out OF the
ground and start devouring every
thing green within their reach.
Fought With Bacteria.
Ralph T. White, entomologist Of
the Agriculture Department. has de-
veloped a type A milky white bac-
terial disease material that spreads
havoc among the grubs. 1t Is a
much less expensive treatment than
the former method Of applying lead
arsenate. The latter is good for
three to five years whereas the new
method is a claimed permanent
treatment.
The general method now being
used in the parks is an application
of the bacterial disease material at
10 foot intervals on all turf areas.
Experiments have been made with
a plot of one acre in the Mall which
was covered solidly. but the cost Is
too great to extend this method to
all areas.
The spot treatment on the aver
age in the Mall reduced the grub
rate from 10 in September. 1910,
to l3 in April. 1912. That Is, from
10 grubs to 13 in a square foot OF
turf.
The greatly reduced number OF
beetles that will be produced from
the surviving grubs are not expect
ed to create a real menace this
summer. When they begin making
their appearance, shrubbery. grass
and trees can be sprayed with lead
arsenate or a simple white paste,
which is equally effective.
The park system lost a lot OF turf
last Fall, due to the Japanese beetle
grub, and the depredations Of the
two previous years were very bad,
Mr.. Rabbit said. Last fall 500
pounds of treatment was applied
in certain downtown areas and gar
deners dug up $4,000 grubs.
Seeding Methods Improved.
The present excellent condition Of
the park lawns is due primarily to
the careful attention they have re-
ceived and improved methods OF
seeding. Mr.. Rabbit said the small
triangles present the toughest prob
lem, chiefly on account OF tres
passers.
Crab grass is as persistent an
enemy as the Jap grubs. One rea-
son the lawns In front Of the public
buildings on Constitution avenue
are now in such good condition Is
because the crab grass was burned
of last Fall with ehemieaA The