Oxford Democrat. [volume] (Paris, Me.) 1833-1933, 1917-08-28
The Stock-Borer In Maine Corn.
REMEDIAL MEASURES FOR 1918 CROP.

Extensive injuries to corn have beef
recently been reported to the Main
Agricultural Experiment Station. Thes
nave been accompanied by specimen
OF the Stockton (Pdpaiqema nitela
which is sometimes called the shear
worm" on account of the manner of th,
attack on corn. Many of the sampler
.eceivee we're farther down in the stall
before the spindle pushed out.
The only direct method of control Il
the removal and destruction of infested
stalks az soon as the presence of tn,
pest is discovered. This, of course, viii
not save the corn stalk of 1917 but It will
reduce the numbers of the insect and
prove one useful preventive for 1918.
There are other control measures
possible with reference to next YEA,
which will be made evident by an
acquaintance with the life history of the
Stalk-Borer "a outlined in the following
account.
The eggs are laid In the fall BY faun.
colored or mouse gray moth where the
young caterpillars can find access to
grass or weeds when they hatch the next
season. The larvae work In the stems
OF these plants while they are very
small but later, on gaining In size, they
seek larger plants with thick stems.
Its feeding habits are recorded In an
Illinois bulletin:
ut Is most noticeable in early spring
In blue. grass, by roadsides, or around
the borders of field, Its presence there
being betrayed by the whitening of
single heads of the grass while all the
rest Of the plant is green. At this time
IL Is of small size, and finds sufficient
food within the grass stem; but later it
Is compelled to resort to thicker. stem
med plants, and It is at this time that 1t
may appear In fields Of corn.
"Going in usually from outside OF the
field, Its injury is, as q rule, almost
wholly confined to the outer rows. It
is probable that where the injury is not
limited to the margins of the field but is
general through out the area, the eggs
are laid in fall In grass or thick-stemmed
weeds In corn-fields, where these have
sprung up protusely after the corn has
been laid by. The burrow which the
stalk borer makes within the stem runs
upwards from the entrance opening,
and Of course varies In size with the
growth of the larva. Sometimes in
leaving the stalk il makes q new hole
above that by which 1t entered. and it
may in this way burrow in succession
several different stalks and several
different kinds of plants.
Besides the corn, wheat and blue
grass already mentioned, 1t may infest
oats and timothy, various garden crops
potatoes, tomatoes, rhubarb,
and spinach-blackberry and raspberry
canes, the thick-stemmed weeds, such
as ragweed, burdock, and cocklebur-a
variety Of garden flowers,
and also the new growth of the peach,
current, grape, apple, willow, etc. In
deed, its food plants are so numerous as
to indicate q practical Indifference to
kinds, the only necessary condition be-
Ing relatively thick stem, soft enough
to allow 1t to enter and feed freely with
In. In small grains and larger grasses,
like oats and timothy, it makes its pre-
sencs manifest by killing or even cutting
off the stem within an encheating leaf,
thus causing the head and the whole
plant above the injury to turn white,
and presently to dry up. 1t is one only
Of several insects which produce this
general effect at this time, but its own
injury may be at once distinguished by
the round hole which 1t leaves in the
stem of the infested plant"
The caterpillar, when full fed, is
about an inch and . quarter long. The
body color varies from purplish brown
to light brown. Five white stripes run
length wise. those along the sides being
on the first four segments
Of the abdomen, giving the caterpillar a
broard, dark band just behind Its
thoracic legs. When the larvs is about
ready to pupate, its whole appearance is
mere dingy and uniform 80 that this
characteristic black band is nearly OBJ
liberated. The head, the top Of the
neck, and the anal shield are pale
reddish yellow.
The insect pupates in Its larval bur
row usually below Its entrance hole.
The pupa is smooth, light brown object
about three-fourths of an inch In length.
1t is from this pupsl case that the
brownish or grayish moth emerges to
lay eggs for the next brood.
As will be seen from this account,
cutting and destroying 10y feeding or
otherwise) the infested stalks one season
will reduce the number of these insects
before they develop to lay eggs for the
next. Clean culture by fall and spring
blowing to destroy the vegetation near
which the eggs are deposited will also
seem logical. Also II grass land adjoin-
ing corn or potato fields or garden
plots shows in spring the work Of the
youns larvae, 1t might be worth while
10 NOW the infested grass and feed 1t
before the caterpillars could escape to
enter the corn.-CHAs. D. WOODS,
Maine Experiment Station.