Evening star. [volume] (Washington, D.C.) 1854-1972, 1929-06-22
beetle INVASION
| MENACES CAPITAL
DESPITE WARE ARE
SWarms of Millions OF 0rien-
tai Pests Are Expected
Within Few Years.
TRAPS ARE DISTRIBUTED
TO HELP FIGHT SPREAD
Science Hopes to Develop Parasite
to Combat Plant Peril
in Nation.
BY THOMAS r. HENRY.

BY THOMAS r. HENRY.
There is every likelihood that swarms
of millions of the dreaded Japanese
beetles will infest the District and the
surrounding countryside In few years,
despite the utmost efforts to check the
growth Of the present infestation.
Such was the prediction Of the Bu-
reau Of Entomology OF the Department
of Agriculture, based on the experience
| Of the Japanese beetle control labora-
| tory at Moorstown. N. j.. where q large
star Of scientists have been engaged III
lighting this Oriental pest for several
years.
The beetles can be controlled 30 that
| they do no Serious damage, but no
means Is known OF actually checking
them. Even If the great majority OF
them in given section were killed each
year enough would be left to propagate
q new brood.
The present gereniol traps. now dis
!, tributed all over Washington by the
plant quarantine division of the depart
ment, are effective means of delaying
| the growth of the infestation, since
every beetle caught In them at this
season probably means great many
! less next year. They also are valuable
| In enabling entomologists to determine
the centers of infestation and to calcu-
late roughly the number of the insects
at large. In addition, the curious OBJ
jects are effective in arousing popular
interest in the beetles.
! KILLERS Are Liberated.
| The final control of the insects, how
ever. probably depends on the develop
ment of some parasite which will feed
upon them. Much work is being done
in this line at the Moorstown station
and several insects have been liberated.
| Visitors to New Jersey early next
month, when literally billions Of the
beetles will be abroad, can get some
idea of what the District eventually
can expect, according to DR.. A. l..
Quaintance. head Of the fruit insects
investigation section of the Bureau of
Entomology. Conditions here, he pointed
out, are almost ideal for the growth OF
| the infestation. The climate Is right,
the beetle has no natural enemies, and
1t finds plenty to eat.
| While the Japanese beetle Is not 30
prolific as many insects, its mortality
rate is very low, DR.. Quaintance pointed
out. Practically its only enemy in this
section is man. The fact that the In
festation here was detected very early
| and control measures started at once,
he indicated. means little. since the
same was true in New Jersey and Penn
/ Sylvania. The 1nfestation grew and
spread in spite Of everything that could
! be done.
Meanwhile the Bureau of Entomology
laboratories is developing more ef-
| fective control methods. A recently
developed method is mixing arsenate Of
lead In the soil Of lawns at the rate of
about 500 pounds to the acre. This is
especially useful on golf courses. It
| kills the grubs and does not injure the
lawn, which would be entirely DESTROYED
If the insects were given q free hand.
Hitherto lawns have been saved by
spraying them with carbon disulphide
emulsion. liquefied gas which sank to
the surface of the soil and "gaSsed" the
gTubs. This practice involved consider
able nuisance. since the gas disappeared
quickly and the operation had to be re-
peated. The arsenate of lead, it was
found, does not break down from acids
In the soil. so that one application Is
good for several years.
Spraying Is Effective Method.
Spraying trees and shrubs with ar
senate Of lead, DR.. Quaintance said. is
the most practical means yet devised,
but 1t has striking disadvantages for
the home. gardener: Ordinarily. it
stains the leaves of flowers with white
streaks. Also 1t is poisonous to domes-
tic animals. An arsenate Of lead prep
aratiOn containing a green dye to off,
set the flrst disadvantage has been
| devised.
Another effective chemical is pyre-
thrum extract, q poison distilled from
the flower heads Of pyrethrum daisies,
which are natives of Asia, the home
land of the beetle. This poison Is not
| injurious to domestic animals and does
not discolor the leaves Compared
with arsenate OF lead, however, 1t is
very expensive.
The control methods already in hand,
DIR. Quaintance pointed out, do not
cause serious economic loss to agri-
culture. 1t loads on the shoulders of
the farmer and nurservman only the
| added expense OF controlling 1t. In
| such community as the District, with
its thousands Of home gardens, however,
1t Is likely to be q source of constant
| irritation.
The traps placed about Washington in
the last few weeks have enabled ento-
mologists to obtain fair idea Of the
extent already reached by the infesta-
ton. The first capture occurred june
| IL. an early record for the beetle. On
June II SIS beetles were taken in the
traps in Arlington County.
Three Centers Of Infestation.
There are three centers of infestation.
The first extends from the north end
Of Potomac Park and through the Capt.:
toll grounds; the second, and worst. 10
about at the junction Of Wisconsin ave-
nue. ana EIllOCC street. In CHEVY Chase,
and the third Is southwest Of Potomac
Yards between st. Elmo and Rosemont,
In Arlington County. It Is expected
that other centers will be found in the
next few weeks.
| Aside from the Japanese beetle in
festation, according to DR.. Quaintance,
| Washington has had fortunate Spring
so far as insects are concerned. The
only new outbreak has been that of
the cherry aphis. which curls the tips
Of cherry shoots and leaves. Many
complaints have been received, but
aside from the ugly appearance it gives
the cherry trees, the aphis causes little
real damage. On large trees 1t Is hardly
worth bothering with. On young trees
1t can be controlled by bending over
the infested shoots into q soap solu-
| ton.
Due to the cold Spring, this has also
been bad year for all sorts of plant
lice. These are conspicuous, but, con-
trary to the general impression, do little
real damage. They need cause little
worry unless It Is seen that they actu-
ally are sucking the strength out of the
4 plant. when effective r1eapa can ha