Garden And Field Insects
=The Cabbage Worm.= The cabbage worm of the early spring garden is a
familiar object, but you may not know that the innocent-looking little
white butterflies hovering about the cabbage patch are laying eggs which
are soon to hatch and make the dreaded cabbage worms. In Fig. 164 _a_
and _b_ show the common cabbage butterfly, _c_ shows several examples of
the caterpillar, and _d_ shows the pupa case. In the pupa stage the
insects pass the winter among the remains of old plants or in near-by
fences or in weeds or bushes. Cleaning up and burning all trash will
destroy many pupae and thus prevent many cabbage worms. In Fig. 164 _e_
and _f_ show the moth and zebra caterpillar; _g_ represents a moth which
is the parent of the small green worm shown at _h_. This worm is a
common foe of the cabbage plant.
_Treatment._ Birds aid in the destruction of this pest. Paris green
mixed with air-slaked lime will also kill many larvae. After the cabbage
has headed, it is very difficult to destroy the worm, but pyrethrum
insect powder used freely is helpful.
=The Chinch Bug.= The chinch bug, attacking as it does such important
crops as wheat, corn, and grasses, is a well-known pest. It probably
causes more money loss than any other garden or field enemy. In Orange
county, North Carolina, farmers were once obliged to suspend
wheat-growing for two years on account of the chinch bug. In one year in
the state of Illinois this bug caused a loss of four million dollars.
_Treatment._ Unfortunately we cannot prevent all of the damage done by
chinch bugs, but we can diminish it somewhat by good clean agriculture.
Destroy the winter homes of the insect by burning dry grass, leaves, and
rubbish in fields and fence rows. Although the insect has wings, it
seldom or never uses them, usually traveling on foot; therefore a deep
furrow around the field to be protected will hinder or stop the progress
of an invasion. The bugs fall into the bottom of the furrow, and may
there be killed by dragging a log up and down the furrow. Write to the
Division of Entomology, Washington, for bulletins on the chinch bug.
Other methods of prevention are to be found in these bulletins.
=The Plant Louse.= The plant louse is very small, but it multiplies with
very great rapidity. During the summer the young are born alive, and it
is only toward fall that eggs are laid. The individuals that hatch from
eggs are generally wingless females, and their young, born alive, are
both winged and wingless. The winged forms fly to other plants and start
new colonies. Plant lice mature in from eight to fourteen days.
The plant louse gives off a sweetish fluid of which some ants are very
fond. You may often see the ants stroking these lice to induce them to
give off a freer flow of the "honey dew." This is really a method of
milking. However friendly and useful these "cows" may be to the ant,
they are enemies to man in destroying so many of his plants.
_Treatment._ These are sucking insects. Poisons therefore do not avail.
They may be killed by spraying with kerosene emulsion or a strong soap
solution or with tobacco water. Lice on cabbages are easily killed by a
mixture of one pound of lye soap in four gallons of warm water.
=The Squash Bug.= The squash bug does its greatest damage to young
plants. To such its attack is often fatal. On larger plants single
leaves may die. This insect is a serious enemy to a crop and is
particularly difficult to get rid of, since it belongs to the class of
sucking insects, not to the biting insects. For this reason poisons are
_Treatment._ About the only practicable remedy is to pick these insects
by hand. We can, however, protect our young plants by small nettings and
thus tide them over the most dangerous period of their lives. These bugs
greatly prefer the squash as food. You can therefore diminish their
attack on your melons, cucumbers, etc. by planting among the melons an
occasional squash plant as a "trap plant." Hand picking will be easier
on a few trap plants than over the whole field. A small board or large
leaf laid beside the young plant often furnishes night shelter for the
bugs. The bugs collected under the board may easily be killed every
=The Flea-Beetle.= The flea-beetle inflicts much damage on the potato,
tomato, eggplant, and other garden plants. The accompanying figure shows
the common striped flea-beetle which lives on the tomato. The larva of
this beetle lives inside of the leaves, mining its way through the leaf
in a real tunnel. Any substance disagreeable to the beetle, such as
plaster, soot, ashes, or tobacco, will repel its attacks on the garden
_a_, larva; _b_, adult. Lines on sides show real length of insects]
=The Weevil.= The weevil is commonly found among seeds. Its attacks are
serious, but the insect may easily be destroyed.
_Treatment._ Put the infected seeds in an air-tight box or bin, placing
on the top of the pile a dish containing carbon disulphide, a
tablespoonful to a bushel of seeds. The fumes of this substance are
heavy and will pass through the mass of seeds below and kill all the
weevils and other animals there. The bin should be closely covered with
canvas or heavy cloth to prevent the fumes from being carried away by
the air. Let the seeds remain thus from two to five days. Repeat the
treatment if any weevils are found alive. Fumigate when the temperature
is 70 deg. Fahrenheit or above. In cold weather or in a loose bin the
treatment is not successful. _Caution:_ Do not approach the bin with a
light, since the fumes of the chemical used are highly inflammable.
=The Hessian Fly.= The Hessian fly does more damage to the wheat crop
than all other insects combined, and probably ranks next to the chinch
bug as the second worst insect enemy of the farmer. It was probably
introduced into this country by the Hessian troops in the War of the
In autumn the insect lays its eggs in the leaves of the wheat. These
hatch into the larvae, which move down into the crown of the plant, where
they pass the winter. There they cause on the plant a slight gall
formation, which injures or kills the plant. In the spring adult flies
emerge and lay eggs. The larvae that hatch feed in the lower joints of
the growing wheat and prevent its proper growth. These larvae pupate and
remain as pupae in the wheat stubble during the summer. The fall brood of
flies appears shortly before the first heavy frost.
_Treatment._ Burn all stubble and trash during July and August. If the
fly is very bad, it is well to leave the stubble unusually high to
insure a rapid spread of the fire. Burn refuse from the
threshing-machine, since this often harbors many larvae or pupae. Follow
the burning by deep plowing, because the burning cannot reach the
insects that are in the base of the plants. Delay the fall planting
until time for heavy frosts.
=The Potato Beetle; Tobacco Worm.= The potato beetle, tobacco worm,
etc., are too well known to need description. Suffice it to say that no
good farmer will neglect to protect his crop from any pest that
The increase, owing to various causes, of insects, of fungi, of
bacterial diseases, makes a study of these pests, of their origin, and
of their prevention a necessary part of a successful farmer's training.
Tillage alone will no longer render orchard, vineyard, and garden
fruitful. Protection from every form of plant enemies must be added to
One way of increasing the yield of fruit]
In dealing with plants, as with human beings, the great object should be
not the cure but the prevention of disease. If disease can be prevented,
it is far too costly to wait for it to develop and then to attempt its
cure. Men of science are studying the new forms of diseases and new
insects as fast as they appear. These men are finding ways of fighting
old and new enemies. Young people who expect to farm should early learn
to follow their advice.
How does the squash bug resemble the plant louse? Is this a true
bug? Gather some eggs and watch the development of the insects in a
breeding-cage. Estimate the damage done to some crops by the
flea-beetle. What is the best method of prevention?
Do you know the large moth that is the mother of the tobacco worm?
You may often see her visiting the blossoms of the Jimson weed.
Some tobacco-growers cultivate a few of these weeds in a tobacco
field. In the blossom they place a little cobalt or "fly-stone" and
sirup. When the tobacco-worm moth visits this flower and sips the
poisoned nectar, she will of course lay no more troublesome eggs.
Next: The Cotton-boll Weevil
Previous: Orchard Insects