The Dupuyer acantha. [volume] (Dupuyer, Mont.) 1894-1904, 1900-08-30
The Canker worm.

Many complaints have been re-
ceived this spring from various locali-
ties in the state in regard to the a n
ker worm, looping caterpillar. or meas
uring worm. as the above insect is
called. The worms are easily distin-
guished from the other ordinary pests
of the orchard by their peculiar loop
ing or measuring mode of travel;
hence the common names. They are
more properly known as canker
worms, and can be found feeding on
apple, cherry, plum, and other fruit
trees and also on elm and other shade
trees.
The eggs are deposited in masses
of a hundred or more on the branches
and trunks of trees on which the
worms feed; the fall canker worm
laying the eggs in the autumn, the
spring canker worm laying her eggs
usually in early spring. In both cases
the eggs hatch while the buds are
expanding, and the larvae feed upon
the leaves until full grown. When
they occur in large numbers they fire.
Quently completely defoliate the
trees. When full grown the larvae
are about an inch in length and they
then crawl down the tree or drop
down by means of a silken thread.
The adults of the fall canker worm
emerge at about the time the first
frosts appear. A few of the spring
canker worms emerge at this time
also, but the vast majority Of them
remain in the pupa state throughout
the winter and emerge as adults at
the first approach of warm weather
early the next spring. In all cases
the adult male canker worm has well
developed wings and can fly. I'm
like most moths, the female canker
worm never has wings at all, and
therefore cannot fly. She crawls to
a suitable tree and ascends the trunk
to the limbs above; there she awaits
the male and then deposits her eggs.
1t at nee becomes evident that If
we can take advantage of the weak
point" in these insects and prevent
the females from crawling up the
trees to deposit their eggs, we can
prevent the injury to the leaves.
This has been done in a number Of
ways. A band of loose cotton, tied
at the top only, or a band of tin fast
ened around the trunk of the tree, or
a band of heavy paper or cloth, on
which is spread tar mixed with oil
to prevent dying, or printers ink,
or even refuse sorghum, will act as
barriers and either prevent the insect
from crawling over, or it will catch
and hold her. Of course, one must
take precaution to stop all crevices
between the band and the bark, after
having first scraped off all loose bark
where the band is placed. When the
females find they cannot crawl up
the tree to deposit their eggs, they
will frequently deposit them at the
base of the tree or on the weeds e
and when the young larvae emerge
they will try to crawl up the tree,
and unless every minute crevice be-
tween the band and the tree be stop
ped, they will crawl through. OF
course, one must attend to the bands
properly and keep them covered with
fresh tar OF other sticky substance.
The tin or cotton bands, of course,
need no sticky substance on them,
since they act as barriers by pre-
venting the insect from getting a
foothold, or by becoming entangled
in the cotton ibers. The bands must
be applied very early in the fall, and
kept there until late in the winter,
and again very early in the spring
sometimes ever in January-and not
removed until summer.
The best and most satisfactory
method, however, of combating the
canker worm is by the use of paris
green. One pound of paris green and
three pounds of lime in one hundred
and twenty-five gallons of water
should be sprayed on to the apple
trees by means of a force pump and
spray nozzle. This spraying should
be done thoroughly, and every part
we'll drenched. Care should be taken
to keep the liquid constantly stirring,
since paris green does not dissolve In
water and settles quickly. Be sure
and purchase paris green that Is pure.
Prof. Stedman. Missouri Agricultural
College, Columbia, Mo.
Thrush.