APPLE-EATERS
“Please tell us about the worm we find in apples and pears,” was
Louis’s request one day when the children were gathered about their
uncle.
“That worm, my lad,” he began, “as I have already briefly explained, is
the grub or larva of a small moth.”
“Seems to me,” interrupted Jules, “the moth is responsible for a good
deal of mischief.”
“Yes, moths do more harm than any other insects; but not as moths, for
these never give us any cause for complaint, being content to suck a
little honey through their slender trumpet from the flowers growing on
every side. It is in the larva state, with appetites of the most varied
sort, that they commit their ravages. I have already told you about
worms that gnaw wood and those that eat woolen stuffs, those that
browse the foliage and those that attack roots. Now we come to some
that give their attention to fruit.
“The best-known of these is the worm that lives in apples and pears. We
usually call it the apple-worm, and its moth is known as the
apple-pyralis. The term pyralis is new to you; it comes from a Greek
word meaning fire, and was long ago ignorantly applied to the
apple-moth because that insect was supposed to eat fire as its regular
diet. Its forward wings are ash-gray streaked crosswise with brown and
ornamented at the tip with a large red spot encircled by a golden-red
border. The rear wings are brown. When the fruit is just beginning to
form, the pyralis lays an egg in the blossom end of apple or pear, no
matter which, and the little worm that soon comes from this egg takes
up its abode close to the seeds. The narrow channel by which it entered
skins over so that the wormy fruit appears intact for some time.
Meanwhile the worm is living in the lap of luxury, with an abundance of
its favorite food all around; but it must have a passage communicating
with the outside so as to get air and make the abode sanitary,
encumbered as it is with refuse and excrement. Accordingly the worm
bores a little tunnel through the flesh of the fruit to the skin and
through this also; there the tunnel ends in a round hole. Through this
passageway the larva receives fresh air and throws out from time to
time the chewed and digested pulp, in the form familiar to us as
reddish wormhole dust. The translucent quality of its skin causes the
worm to vary in hue according to the color of what it eats, being
sometimes white, sometimes brown or yellow, and sometimes pink. It is
ornamented with little black tubercles or pimples arranged in pairs.
The head and the first ring-like section of the body are brown.
“Apples and pears containing worms continue to grow; indeed, they ripen
sooner than the others, but it is a sickly maturity that hastens the
fall of the fruit. As a rule, the larva in wormy fruit that has fallen
to the ground is by that time fully grown; accordingly, it leaves its
domicile by the passage already made and creeps into some crevice in
the bark of a tree, or sometimes it retires underground, after which it
makes for itself a shell of silk mixed with fragments of wood or dead
leaves, and turns into a moth the next year, when all the young apples
and pears are ready to receive its eggs for the new generation.
“In plums and apricots is found a worm closely resembling that
infesting apples and pears; another occurs in chestnuts, and a third in
pea-pods, the tender young peas furnishing excellent food for the
intruder. All these worms are the larvæ of moths commonly named from
the fruit or vegetable they infest. The pea-worm, after it has devoured
the best part of the pod’s contents, passes into another pod by boring
a round hole. Its moth appears in June, and the larva in July and
August. Consequently, spring peas are never wormy, while those of late
summer very often are. This example shows you how, in certain
instances, a crop can be saved by hastening or delaying the sowing,
according to the time when the ravagers may be expected to appear.”
“But no such plan can be carried out with chestnuts,” said Emile. “That
is plain enough, for chestnut-trees bear their nuts at a fixed time,
and we can’t hurry them up or keep them back. The chestnut-moth comes
just when the table is set for its young ones. What disgusting-looking
worms they are, too—all red and soaked in their own juice in the
chestnut-meat!”
“We can’t do anything, either, for the apple-trees and the pear-trees,
can we?” Louis inquired.
“Not much. Some people gather the wormy apples and pears fallen from or
still on the trees, and crush them to kill the worms inside. That makes
so many enemies the fewer for the following year; but again it has to
be admitted that, left to our own resources, we could never defend
ourselves against the pyralis and other similar moths that produce
larvæ from which hardly anything is safe. Fortunately the swallow
catches these moths on the wing, bats chase them assiduously in the
twilight, and the little gray lizard snaps them up when they alight on
the trunks of trees. These are so many friends, protectors of our
gardens and orchards.”
“The moths you call by that queer name, pyralis—are there a good many
of them?” asked Jules.
“There are numerous species, and each species is represented by
countless legions of individual moths. Some of these attack fruit; I
have just told you about the principal ones. Others have a different
mode of life, and of these I will speak to-morrow. But they are all
very small moths, and some are beautifully colored. Their antennæ are
fine and their wings, rounding at the shoulders, spread out in the form
of a cape and are folded together in repose like the two halves of a
sloping roof; that is, they incline to right and left. Their grubs have
a smooth and shiny skin. These worms draw back quickly when molested
and let themselves fall to the ground, deadening the shock of the fall
by means of a silk thread that holds them suspended by the lip.”
“That’s a clever trick,” Emile observed. “As soon as the worm is
frightened it glues the end of the thread to something and down it
drops, but gently and only as fast as the thread is let out by the
spinneret.”
“This morning,” said Jules, “Mother Ambroisine was picking over some
dried peas. A few were pierced with a round hole, and others had a
little brown insect spotted with white. Peas, then, have two enemies:
the pyralis-worm that eats fresh fruit and the insect I am speaking of
that eats them dry.”
“The insect that eats dried peas is a small beetle, a weevil with a
wide and very short snout. It is known as the pea-weevil. Another
weevil eats beans, and still another lentils. It is always the larva
that does the mischief. Once arrived at the perfect state, the weevil
bores a round hole in the seed and gets out. These weevils have the
same habits as the grain-weevil. They are destroyed by the use of
sulphide of carbon, or simply by the action of heat if the seeds they
infest are not to be sown, for the temperature required to kill the
insects and their larvæ would also destroy the germinative principle of
the seed.”