Barton County democrat., 1909-06-11
sequently decrease the yield.
Preventive Measures.

IIeNeullNe MtdSuIts.
Rotation of crops is the most eff
fective preventive of root-worms.
The beetles of the root-worms usually
deposit their eggs in the old infested
fields. By changing the corn from
such field to one which was not il
corn the preceding year, these eggs I
are left behind.
There are two kinds of these root
worms: the Northern corn root
worm" and the Southern corn root
worm" since the habits of the two
are very different in some essential
points, a few further remarks con- :,
cerning them are given below. The
two are easily distinguished in the
beetle stage, when they are commonly
found on the corn silk in the fall
The Northern Corn ROot-Worm.
The northern form of the rOo.- |
worm in its adult stage is a plain,
grass green beetle, about one-ffth Of
an inch long. In the fall these small
green beetles are common objects on
the silk of the corn and the flowers of
the golden rod. The spotted beetle Of
the Southern corn root-worm is fire.
auently found along with the plain
green beetle. The beetles deposit
their tiny eggs in the soil near the
stalks of corn.
The next year these eggs hatch out
young root-worms which begin to at
tack the corn almost as soon as 1t Is
out of the ground. Throughout the
summer these northern corn root
worms are at work on the roots until
the worms become full grown in the
late summer. When they become ma
ture they transform to the pupa, or
resting stage, in which stage they
spend a short time. Finally the plain
green beetle emerges from this pupa.
The beetles then deposit their eggs
for another crop of root-worms for
the next year. As far as it is known
there is but one breed of this form in
season.
{ =. The Southern Corn Root-Worm. :.
: The beetle of the southern root
worm is green, with twelve black
! spots on its back. On this account ii
!. may be easily distinguished from the
other form. 1t is also somewhat lar
ger than the plain green beetle, meas
uring about a quarter of an iuch long
The black spots are in three rows
across the back of the beetle, each
row with four spots. Usually thesC
beetles are found along with the plair
green beetles on the silks of the corn
{ but they are not so common. The
] black spotted beetles are found moi
2 only in the fall, but all through The
: season from early spring as well
{ There SENS to be at least two brood'
). of them during the year.
>, The life history Of tie southern
corn root worm IS similar 10 that Of
the northern form, except that it II
] passed through n a much shorter
time. In the corn field the eggs are
deposited in the ground near the
s stalks.
Comparison of the Two Forms.
Corn is praet cally the only foOt
plant Of the northern rOot-wom. |
I is rarely found in sorghum. On th,
= other hand, the southern rOot-wOrm
have been found in wheat, rye, mile.
and other grasses. The northern
form does more injury to corn, al
,, though during the last year tb
beetles of the southern form were eS
I tremely common in Iowa. Since thy
r northern corn root-worm has practi
s cally only one food plant, corn, in it
|. grub stage, there need be no especla
difficulty in avoiding its ravages. !
Il mere change of crops will bring relief
;, With the southern form the problem
i is more difficult, but it is usually no
: the southern rOot-wom which doe
the really serious damage in this stat
L Where either the plain green beetl
n or the black spotted beetle were seel
Lt in very large numbers feeding Oh
the silks of the corn last fall, il is al
Il indication that a corn field on tn
same piece of ground will be infested
:, with the root-worms this year
Where a proper rotation of crops i
put into effect there need be littlt
Q trouble with these root-woms.