Evening star., 1942-05-02
Of Stars, Men
And Atoms
Notebook Of Science Progress
In Laboratory, Field
And Study
By Thomas r. Henru.

- ''S'''oo Ah' ~1S''
An Axis invader which got its first
foothold in New England 80 years ago
has advanced, its numbers increased to
many millions, to positions from which
it is threatening Americas great corn
belt.
This is a little moth known as the
European corn borer. In the iarva stage
it bores into the stalks and ears of corn,
greatly cuts down yields and may ruin
a crop. 1t was introduced. experts of
the United States Bureau of Entomology
believe, either from Italy or Hungary
shortly after 1910 and ever since has
been moving westward step by step For
years it had been recognized in Central
Europe as one of the most destructive
of grain pests. Some years its area was
extended only a few miles but in other
seasons it would push on 100 miles or
more.
The latest insect pest survey report
to the Department of Agriculture shows
that during the past year it has oc
cupied 26 new counties in Illinois. so
that it now covers the eastern half Of
the State, and is moving West to the
Mississippi River through some of the
Northern counties. 1t also spread into
IS new counties in Western Indiana
bringing tWo-thirds of that State into
the danger zone The longer it is estab-
lished the faster it moves and may
necesstate far-reaching changes in
methods of n-harvesting
Methods adopted in the past have
been effective only in keeping the pest
under control, not in stopping its prog
ress. Department of Agriculture corn
breeding specialists have just announced,
however, that they have succeeded in
producing varieties of corn which ap-
parently are immune to the pest 1t
probably will be possible to isolate the
factor responsible for this immunity
and breed it into better yielding varie-
ties
They hope to have the new varieties
ready before the "blitz" on the Midwest
cornfelds becomes much more serious.
AS yet, however, these are in an expert
mental stage and no large-scale produc-
ton of seed has been attempted. In
Central Europe the destructiveness of
the bug has been cut down in two ways
1t has been established there for long
time-perhaps centuries. AS usually
happens, sort of balance has been
struck in nature. Other insects, chiefly
tiny wasps, have evolved to feed on the
larvae. There was no natural enemy
in the New World.
More than 100000 of these insects
have been released from year to year
through the corn-borer infested regions,
after careful investigation to determine
that they themselves would not injure
crops. In some cases they have de-
stroyed more than half of a brood but
the experts have about given up hope
that they can be relied upon to turn
back the destructive little bug
Central European farmers learned
long ago that the most effective defense
was to clean up fields thoroughly after
each harvest so that there would be no
rottlng stalks in which the insects could
spend the winter. This has been ex-
pensive and might be extremely so in
parts of the United States unless some
use could be found for the dead stalks
The corn borer moths, experiments
here have shown, are exceptionally
strong flyers. They can cover 20 miles
or more in a single hop. Large bodies
of water do not check their flight They
have been observed to alight on the sur
face and then take of again. 1t is
known that the larvae can withstand
long periods of submersion in fresh or
salt water when hidden in cornstalks,
so that they probably are carried to
considerable distances by the currents
Of rivers and lakes