The Emporia weekly news. [volume] (Emporia, Kan.) 1881-1889, 1882-10-12
CONCERNING CHINCM BUGS.
Suggestions as TO the Best Means {
Checking Their Increase.

Suggestions rs to the Best Means OF
Checking Their Increase.
Prof. S. A. Forbes, state entomologist
of Illinois, makes the following report
to the bureau of agriculture in regard
to the ravages of this insect and the best
means of checking its increase:
The history of the chinch bug this
season has been unusual and peculiarly
interesting, Ordinarily, as reported in
previous years, the old bugs which live
through the winter have laid their
eggs In April and May, in fields Of wheat
and other small grains, and upon these
crops the first brood has expended its
principal energies. AT harvest time,
when some members OF this brood are
usually fully developed and others but
partly grown, a migration to cornfields
takes place, and IN these the second
brood is chiefly produced and gets its
growth. 1t is the survivors of this brood
which hibernate and lay their eggs in
the spring. From this it follows that
the bugs are commonly widely scattered
in the fields of small grain which they
infest, but, invading the cornfields from
the outside, confine their principal dep
relations to the outer part OF each field.
During the present season the old
bugs appeared at the usual time in eX.
traordinary numbers, threatening SER
ious injury TO all the field crops; but
the long continued cool and rainy
weather had the effect partly TO delay
the deposition of the eggs, and partly,
perhaps, to destroy such as were laid, so
that in central Illinois the young bugs
did not appear until about the first of
July, by which time the small grains
were nearly or quite out of their way.
The eggs therefore were laid chiefly In
corn, brOOm-eor aud sorghum, and the
bugs were OF course widely scattered
through the fields For this reason, al
though the number occurring in sever
al fields was sufficient to do great and
conspicuous mischief if they had enter
ed the corn in masses from without, as
ia their ordinary practice, the same num-
Der uniformlylscattered have attracted
little attention and do relatively little
harm. In short, the bugs did not ap-
probably damage the small grain, be.
cause their development was retarded
until these crops were beyond their
reach, and they have injured corn and
similar crops because they were widely
scattered through the fields instead OF
being concentrated in hordes,
This condition of affairs has one inn
portaut consequence. We must not
Judge of the number of bugs now alive,
and the amount of the injury which
they threaten another year, by the in
jury now apparent. They are in fact
many times more abundant In central
Illinois than the damage attributed to
them would lead US to suppose; and
every precaution should be taken to
prevent a serious outbreak of them next
season.
Search should be made for them in
fall and early winter among cornstalks
and in grass, weeds and trash about
fields and under leaves in woodlands,
and whenever they are found hlbernat-
ing in such situations they should be
burned, if possible, in the rubbish which
shelters them. The exposure of piles
Of rubbish in fields where they abound,
and subsequent burning with the bugs
which take shelter under il, is an expo
dient we'll worth trying.
IL Is to be feared that very much more
reliance is generally placed upon the
influence of wet weather in limiting the
rayages of the bugs than the truth will
warrant Careful experiments made at
the state laboratory of natural history
in July showed that a thorough drench-
ing Of the corn and ground daily for
ten successive days, did not affect the
bugs in number or vigor, or in any ap-
preeinble way.
In affected corn fields large numbers
of a small, light brown ant ( LdciuS
1lIflls) are found running over the
stalks and secreted under clOds az the
base of the hills. AS one of these may
rarely be seen with a young chinch bug
in its mouth, this ant has been reckoned
by many serviceable enemy of the
pest. have lately made careful disco
lions of q number of these taken from
among the chineh bugs, but have found
only liquid vegetable food IN their
stoaaachs. They probably feed almost
wholly on exudations from the corn and
the fluid eKeremept of the bugs
4 "A small predacsous beetle 4 44qoEslef-
Gus conaBld) has also been ab1ndsnt in
the same situations. Dissections of this
have proven that young chinch- bugs
form about 20 per cent of its food, plant
lice making another 10 per cent. On
the other hand the remainder of the food
is vegetation, apparently derived from
the roots of the corn.
have lately found the chinch- bug is
extremely subject TO a minutes interal
parasite, a species of bdcterium about
two thoGsandths of an inch in length,
the spread and multiplication of which
may account for those sudden disap-
pearances of vast numbers of the bugs
which have hitherto been attributed
wholly 70 the weather.
Experiments nov in progress at the
laboratory and in the field have already
shown that the chineh- bag is EerY easily
killed By the application q : week
emulsion Of kerosene and soaRs9ds, Ethe
materials for which cost about three
-foarths of q cent q gallon. Experiments
are now under way for the discovery OF
cheap and effective methods of supply
ing this and other insecticides on large
scale.