Iron County register. [volume] (Ironton, Iron County, Mo.) 1867-1965, 1883-07-05
The New Wheat Insect Pest.

Professor Forbes, the Illinois State
Entomologist, has been investigating
the new winter wheat pest, and de-
scribes it as follows:
A new insect enemy of winter wheat
has lately come to notice in Central and
Southern Illinois, where it has done
most serious mischief in some localities,
and, as it will soon be too late to make
observations upon it, the immediate at
tention of those interested is earnestly
invited to this subject. Wherever it
has thus far been detected, it has pre-
viously been confounded with the Hes
sian fly, and it is not impossible that
much of the damage attributed to the
latter insect in the southern part of the
State is really due to this hitherto I'M
known pest.
In the form in which it may now be
found in the wheat it is smooth, slender,
pale-green grub, about one-fourth of an
inch in length, without distinct head or
feet, tapering nearly to point ut one
end (the anterior), and slightly mar
rowed but thicker at the other. At the
pointed end, two curved black hooks
may be seen, working actively back
ward, as long as the larva is alive.
These are the jaws and are used for
scraping away the substance of the plant.
If the head is examined with good
magnifier, two very short antenna,
scarcely longer than wide, may be seen
near its upper surface, and below these
are two circular areas, probably repre-
senting palpi. On each side of the base
of the second seEment of the worm is 4
small gill-like a6pendage, divided into
two lobes. each ODE with six divisions.
The last segment of the body is bi-lobed,
and bears upon its posterior surface
two openings (spiracles), each guard
ed by circlet of about twelve de-
pressed spines.i The larva is now
changing in thu southern part of the
State into the pupa or chrysalis. which
has the same general appearance and
color as the grub, but is short and thick.
with blunt ends, and has not the power
of motion. 1t las no appearance of
wing cases or otaer appendages. AL
though the general effect of this insect
upon the growing wheat is not especial
ly different fronS that produced by the
Hessian fly, the Worm itself can be very
readily distinguished, especially at this
season of the yea, since the Hessian fly
is no longer a free grub, but constructed
for itself last fai a dark brown, fiat,
oval case, like YAK seed, from which
it is now emerging as perfect fly.
The insect is how burrowing in the
base of the stem of wheat just above
the root; and I'll E pupa occurs in the
same position. 1.-The effect is to stop
the growth of thd plant, and ultimately
to kill it. There is abundant evidence
that the grub leaves one stalk for an
other, SO that single insect may per-
haps destroy an entire stool. Fields in
Fulton County have been completely
ruined by this Hest, SO that they arc
now being plowe1 up for other crops.
Where the injury is less complete, it
has the effect to deaden the wheat,
more or less com pletely, in spots. The
insect may be found by carefully strip
ping down the leaves of the affected
stems until the center is reached, where.
if it still remains, it will be found
buried at the base of the growing stem.
As this insect has only been known
to us for few weeks it is, of course.
impossible to give any sufficient account
of its development. 1t is certain. how
ever, that the worms were Matched in
the field in the fall. after the wheat was
sown, and that the principal part of
the injury was done before frost. 1t
will now soon transform into n minute
fly. which will probably rear second
brood later in the season. This fly will
be no larger than mosquito. but
much thicker and more robust.
A clergyman has actually been