Semi-weekly herald., 1908-08-20

Ah"uy tniDks ADJUSTED tnomBofye8 20
that proper checks wero established.
and at the present time. though ths
midge often becomes no abundant -
to threaten serious injury to the crop.
1t never quite reaches that point. The
reason Ia simply that It's enemies keep
II down. II those enemies were swept
out OF existence. even temporarily, m
ravages would be on q disastruus
scale.
A recent experiment was aimed at
the green bug''--a species Of plant
lcuse which did enormous mischief IN
the southwest last year. In a. much
MS this insect begins its work In the
south, gradually extending its opera
tions northward with the advance Of
the season. 1t seemed practicable to
collect great numbers Of specimens OF
its principal enemy in the southern
fields. and, by throwing them in ad-
vance of the pest, to head 1t off, SO
to speak. The attempt, however. was
not successful, nature evidently pre-
ferring her own methods.
The enemy referred to is very mi.
mute four-winged fly, called Lysiphle-
bus. Crawling over an infested plant.
II lays an egg In the body Of each
green bug It meets. The eggs thus
deposited quickly hatch. and the lar
vac feed upon the vitals OF the vic.
Tins, preventing them from breeding,
and finally killing them. AT the end
of time days they cut their way out
and appear M flies. ready to start
the performance over again by laying
their own eggs In more green bugs.
By this means the pest is soon dis
posed OF. A plague of green bugs
(such as occurred last year in Texas
and Oklahoma. doing $4,000 900 worth
OF damage to wheat and oats) arrives
only when cold spring follows = mild
winter. Under such conditions great
Of the bugs live over win
ter. multiplying continuously, while
their little foes. which can not breed
when the temperature Ia below sc de-
grees, do not have chance to get in
Iheir work until the season Is far ad-
vanced.
The army worm ito cite another ex-
ample in point) is naked striped
caterpillar an inch and quarter long.
which makes its appearance In early
devouring grains and grasses.
II climbs the seed stalks and cuts off
he heads. Under favorable conditions
II multIplies In fabulous numbers. and.
in search OF food, travels
and feeds both day and night, inflict
ng enormous damage. The crops quick.
ly disappear before the march OF its
legions. Eventually. when
full fed, 1t burrows into the ground.
from which It emerges later as q
large brown miller.
Now. anybody who goes about in =
field that is being devastated by these
worms will notice that many. and even
majority of them have small white
spots on their bodies. These are the
eggs Of little fly that looks somewhat
like housefly. and which Is known to
science ms Winthemia. When they are
hatched the grubs that emerge from
them will bore through the skins OF
the caterpillars and feed on their VI
tails. This will not prevent the worms
from doing damage. but It Will render
them incapable OF transforming into
the adult form-of becoming moths.
In other words. Only those indfvid-
uals which escape attack by the para
site will survive to perpetuate their
species-the result being that the pest
is 30 nearly extsrminated that several
years usually elapse before 1t again 90
ours in sufficient numbers to make
serious trouble.
After the caterpIllars have disap
peared from an infested field, one who
Visits It will nnd there great numbers
OF the little flies. buzzing and droning
like a swarm Of bees. Their pres
ence affords the best possible guaran-
tee that there will be no renewal oe
the plague during the following sear
son. What happens under such con
ditions Is made manifest II one takes
the trouble to collect quantity of the
worms and put them into box cover
ed with wire net. It will be found that
many flies are reared. but almost NO
millers.
This is very new country. especial
ly In the agricultural sense, and ma
ture's balance has been thrown tempo
rarily out Of gear. 80 to speak, by|
mans interference.
In the forthcoming year book Of ths|
department of agriculture viii bel
found an extended discussion OF this|
interesting subject. from. the pen ID
one OF the experts Of the bureau a
insects, Mr.. +. M. Webster, to whoU|
the writer is indebted for this mai
terial. He compares the working a
parasItisn in the insect kingdom q
that Of well organized IRE depart
ment In large city. There alwayi
have been. he says, and probably Il
ways will be, occasional disastrous con
flagrations in such cities. but this fac