THE APPLE WORM
[Illustration: Apple worms in core of apple. Usually only one worm
appears in an apple. Note the decaying of the apple.]
This is perhaps the most destructive insect pest attacking the apple.
Every year, that we have a good apple crop, there are thousands of
bushels of wormy apples which are practically worthless. This means an
actual loss of thousands of dollars a year to the apple growers of this
country. For this reason alone each child should come to know the life
history, habits and injury of this pest. It is most destructive to the
apple though the pear comes in for its share.
[Illustration: The codling moth slightly enlarged. (From Slingerland).]
Every country child and many of those of the cities, are familiar with
this worm for they often bite into it while eating apples. The small
worms crawl down in the blossom end of the young developing apple and
from there bore into the pulp and eventually reach the core of the
fruit. They stay in the apple about six weeks when they eat a hole out
to the surface and crawl down to the trunk where loose bark offers a
hiding place. Here they spin their cocoons and change to a small,
brown, plump pupa and after a few days the winged moth emerges. The moth
is very small and is not often found by one not acquainted with it. They
come out during late June and early July when they lay eggs for a second
colony of worms which again enter the fruit and destroy more of it.
These worms of the second brood are usually mature and leave the fruit
about the time apples are picked in the fall in central Missouri. They
escape and soon spin cocoons in which they pass the winter. Early in the
spring these change to pupae and later the moths come out. They appear
about the time apples bloom in the spring and lay the eggs for the first
worms which enter in great numbers at the blossom end.
This in short, is the life story of the pest through the year. Little
can be done to destroy the pest after it gets into the fruit, therefore
remedies must be applied to destroy the worm before it gets into the
fruit. All orchards should be sprayed with a poison in the spring
before the worms appear. Since most of them enter by way of the blossom
end, it is necessary that the poison be put into the blossom end. To do
this spray at once after the blossoms fall, repeat after two weeks and
spray again in July to kill the second brood of worms. The protection of
woodpeckers and sapsuckers will also help as they feed on the worms
under the bark.
[Illustration: Apple blossoms at about the right stage for receiving the
first and most important arsenical spray for the control of the apple
worm.]
OBSERVATIONS AND BREEDING WORK
Go into the orchard and examine for apples with masses of sawdust-like
material projecting from the sides or blossom end. By removing this
brown deposit which is the excrement of the worm, you will find a hole
leading into the apple. Cut open one of these and determine the course
of the tunnel. Where do you find the worm? Do all such apples contain
worms? Where have they gone? How does the feeding of the worms injure
the fruit? Do any of the wormy apples show rot? Are any of the windfalls
in the orchard wormy and if so what proportion?
Remove a worm from one of the apples and examine it. How many legs has
it? What color is it and does it have hair upon its body? Can it crawl
fast? Does it spin silk? Put a number of the large worms in a jar and
examine from day to day and keep records of what happens. Collect a
number in the fall and keep them in a box outdoors during the winter. In
the spring watch them change to the pupa in the cocoon and a little
later the mature insect or codling moth, as it is commonly called, will
emerge. Describe the moth and pin a number of them for your collection.
What time in the spring do the caterpillars change to the pupa and when
do the moths emerge? If you keep the moths in a bottle they will lay
their small circular flat eggs where they can be seen by looking
closely. During the winter examine under the bark of apple trees and in
cracks and crevices about apple pens for the small silk cocoons
containing the worms. Examine in the same places in the spring about
apple blooming time and then in place of the small pink worms you will
find the small brown pupae. Keep these a few days and the moths will
appear.
What proportion of apples in your region are wormy? What are they used
for? Are the trees sprayed just after the blossoms fall to control the
pest? Where spraying is carefully done, are there as many wormy apples?
Why not spray all the orchards properly and have no worms?
Draw and describe the different stages of the apple worm or codling moth
and its injury to fruit.
* * * * *
"_O, yet we trust that somehow good
Will be the final goal of ill,
To pangs of nature, sins of will,
Defects of doubt and taints of blood;_
"_That nothing walks with aimless feet;
That not one life shall be destroyed,
Or cast as rubbish to the void,
When God hath made the pile complete;_
"_That not a worm is cloven in vain,
That not a moth with vain desire,
Is shrivelled in a fruitless fire,
Or but subserves another's gain._"
--TENNYSON.