Northern tribune. [volume] (Cheboygan, Mich.) 1875-1885, 1883-05-19
The COrn-ROOt Worm.

The corn-root worm, in the form in
which it affects the roots of corn, is n
slender, white grub, not thicker than a
pin, from One-fourth to three-eighths of
an inch in length, with a small, brown
head, and six very short legs. 1t CON-
mences its attack in May or June,
usually at some distance from the stalk,
toward which it eats its way beneath
the epidermis, killing the root as fast as
it proceeds. Late in July or early in
August it transforms in the ground near
the base of the hill, changing into
white pupa, about Observation-Disclosures of
an inch long and two-thirds that width,
looking somewhat like an adult beetle,
but with the wings and wing-covers
rudimentary, and with the legs closely
drawn up against the body. A few
days later it energies as perfect insect
about one-fifth of an inch in length,
varying in color from pale greenish-
brown to bright grass-green, and usual
ly without spots or markings of any
kind. The beetle climbs up the stalk,
living on fallen pollen and upon the
silk at the tip of the ear, until the latter
dies, when few of the beetles creep
down between the husks and feed upon
the corn itself, while others resort for
food to the pollen of such weeds in the
field as are at that time in blossom. In
September and October the eggs are
laid in the ground upon or about the
roots of the corn, and most of the
beetles soon after disappear from the
field. They may ordinarily be found
upon the late blooming plants, feeding
as usual upon the pollen of the flowers,
and also to some extent upon molds
and other fungi, and upon decaying
vegetation.
There can be no further doubt that
the insect is single-brooded, that it
hibernates in the egg, as a rule, and
ground has been plowed and planted to
corn in the spring, probably in May and
June. Although the adult beetles,
when numerous, do some harm by eat
ing the silk before the kernels are fer
tilted by the pollen, and also OCCASION
ally destroy few kernels in the tip of
the ear, yet the principal injury Is done
by the larva in its attack upon the roots.
Although the roots penetrated by the
larvae die and decay, thrifty corn will
throw out new ones to replace those
lost. The hold of the stalk upon the
ground is often so weakened that q
slight wind is sufficient to PROSTATE the
corn. Under these circumstances it
will often throw out new roots from the
joints above the ground, thus rallying,
to certain extent, against serious in
jury. AS the results of numerous OBJ
servations, it is seen that little or no
mischief is done except in fields that
have been in corn during the year or
two preceding, and frequent change
of crops is, therefore, complete pre-.
ventive. Beyond this, the life history
of the insect gives us little hope of fight
ing it effectually, except at too great ex-
pense, as the eggs and worms are scat
tered and hidden in the ground, and
the perfect beetle is widely dispersed
throu ghout the field.
This insect was first described by Say,
who found it near the Rocky Mountains.
Its ravages upon corn were first noted
by Riley, in his report to the Department
of Agriculture for 1S7S.-Rrof. Forbes.