PROTECTING PLANTS FROM THINGS THAT PREY ON THEM - Continued
The bronze birch borer is destroying many fine white birch trees in some
parts of the country. Its presence is known by the dying of the top of
the tree. There yet is no known way of preventing this borer from
attacking white birches, and the only practicable and effective method
so far found for checking its ravages is promptly to cut and burn the
infested trees in autumn, in winter, or before May 1. There is no
probability of saving a tree when the top branches are dead, although
cutting out the dead parts may stay the trouble temporarily. Cut and
burn such trees at once and thus prevent the spread of the insect.
Bud-moth on apple.--The small brown caterpillars with black heads
devour the tender leaves and flowers of the opening apple buds in early
spring. Make two applications of either 1 lb. Paris green or 4 lb.
arsenate of lead in 100 gal. of water; the first when the leaf-tips
appear and the second just before the blossoms open. If necessary, spray
again after the blossoms fall.
Cabbage and cauliflower insects.--The green caterpillars that eat
cabbage leaves and heads hatch from eggs laid by the common white
butterfly (Fig. 295). There are several broods every season. If plants
are not heading, spray with kerosene emulsion or with Paris green to
which the sticker has been added. If heading, apply hellebore.
The cabbage aphides, small mealy plant-lice, are especially troublesome
during cool, dry seasons when their natural enemies are less active.
Before the plants begin to head, spray with kerosene emulsion diluted
with 6 parts of water, or whale-oil soap, 1 lb. in 6 gal. of water.
The white maggots that feed on the roots hatch from eggs laid near the
plant at the surface of the ground by a small fly somewhat resembling
the common house fly. Hollow out the earth slightly around every plant
and freely apply carbolic acid emulsion diluted with 30 parts of water.
Begin the treatment early, a day or two after the plants are up or the
next day after they are set out. Repeat the application every 7 to 10
days until the latter part of May. It has also been found to be
practicable to protect the plants by the use of tightly fitting cards
cut from tarred paper. (See page 187.)
Canker-worms.--These caterpillars are small measuring-worms or loopers
that defoliate apple trees in May and June (Fig. 217). The female moths
are wingless, and in late fall or early spring crawl up the trunks of
the trees to lay their eggs on the branches. Spray thoroughly once or
twice, before the blossoms open, with 1 lb. Paris green or 4 lb.
arsenate of lead in 100 gal. of water. Repeat the application after the
blossoms fall. Prevent the ascent of the wingless females by means of
sticky bands or wire-screen traps.
Case-bearers on apple.--The small caterpillars live in pistol-shaped
or cigar-shaped cases, about 1/4 in. long. They appear in spring on the
opening buds at the same time as the bud-moth and may be controlled by
the same means.
Codlin-moth.--The codlin-moth lays the eggs that produce the pinkish
caterpillar which causes a large proportion of wormy apples and pears.
The eggs are laid by a small moth on the leaves and on the skin of the
fruit. Most of the caterpillars enter the apple at the blossom end. When
the petals fall, the calyx is open and this is the time to spray. The
calyx soon closes and keeps the poison inside ready for the young
caterpillar's first meal. After the calyx has closed, it is too late to
spray effectively. The caterpillars become full grown in July and
August, leave the fruit, crawl down on the trunk, and there most of them
spin cocoons under the loose bark. In most parts of the country there
are two broods annually. Immediately after the blossoms fall, spray with
1 lb. Paris green or 4 lb. arsenate of lead in 100 gal. of water. Repeat
the application 7 to 10 days later. Use burlap bands on trunks, killing
all caterpillars under them every ten days from July 1 to August 1, and
once later before winter.
Cucurbit (cucumber, melon, and squash) insects.--Yellow,
black-striped beetles appear in numbers and attack the plants as soon
as they are up. Plant early squashes as a trap-crop around the field.
Protect the vines with screens (Fig. 229) until they begin to run, or
keep them covered with bordeaux mixture, thus making them distasteful to
the beetles.
Squash vines are frequently killed by a white caterpillar that burrows
in the stem near the base of the plant. Plant a few early squashes
between the rows of the late varieties as a trap-crop. As soon as the
early crop is harvested, remove and burn the vines. When the vines are
long enough, cover them at the joints with earth in order to develop
secondary root systems for the plant in case the main stem is injured.
Dark green plant-lice feed on the under sides of squash leaves, causing
them to curl and wither. Spray with kerosene emulsion diluted with 6
parts of water. It is necessary thoroughly to cover the under side of
the leaves; the sprayer, therefore, must be fitted with an upturned
nozzle. Burn the vines as soon as the crop is harvested and keep down
all weeds.
The stink-bug is very troublesome to squashes. The rusty-black adult
emerges from hibernation in spring and lays its eggs on the under side
of the leaves. The nymphs suck the sap from the leaves and stalks,
causing serious injury. Trap the adults under boards in the spring.
Examine the leaves for the smooth shining brownish eggs and destroy
them. The young nymphs may be killed with kerosene emulsion.
Curculio.--The adult curculio of the plum and peach is a small
snout-beetle that inserts its eggs under the skin of the fruit and then
makes a characteristic crescent-shaped cut beneath it. The grub feeds
within the fruit and causes it to drop. When full grown, it enters the
ground, changes in late summer to the beetle, which finally goes into
hibernation in sheltered places. Spray plums just after blossoms fall
with arsenate of lead, 6 to 8 lb. in 100 gal. of water, and repeat the
application in about a week. After the fruit has set, jar the trees
daily over a sheet or curculio-catcher and destroy the beetles; this is
practically the only procedure for peaches, for they cannot be sprayed.
The quince curculio is somewhat larger than that infesting the plum and
differs in its life-history. The grubs leave the fruits in the fall and
enter the ground, where they hibernate and transform to adults the next
May, June, or July, depending on the season. When the adults appear, jar
them from the tree on sheets or curculio-catchers and destroy them. To
determine when they appear, jar a few trees daily, beginning the latter
part of May in New York.
Currant-worm.--In the spring the small green, black-spotted larvae
feed on the foliage of currants and gooseberries, beginning their work
on the lower leaves. A second brood occurs in early summer. When worms
first appear, spray with 1 lb. Paris green or 4 lb. arsenate of lead in
100 gal. of water. Ordinarily the poison should be combined with
bordeaux (for leaf-spot).
Cut-worms.--Probably the remedy for cut-worms most often practiced in
gardens, and which cannot fail to be effective when faithfully carried
out, is hand-picking with lanterns at night or digging them out from
around the base of the infested plants during the day. Bushels of
cut-worms have been gathered in this way, and with profit. When from
some cause success does not attend the use of the poisoned baits, to be
discussed next, hand-picking is the only other method yet recommended
that can be relied upon to check cut-worm depredations.
The best methods yet devised for killing cut-worms in any situation are
the poisoned baits, using Paris green or arsenate of lead for the
purpose. Poisoned bunches of clover or weeds have been thoroughly
tested, even by the wagon-load, over large areas, and nearly all have
reported them very effective; lamb's quarters (pigweed), pepper-grass,
and mullein are among the weeds especially attractive to cutworms. On
small areas the making of the baits is done by hand, but they have been
prepared on a large scale by spraying the plants in the field, cutting
them with a scythe or machine, and pitching them from wagons in small
bunches wherever desired. Distributed a few feet apart, between rows of
garden plants at nightfall, they have attracted and killed enough
cut-worms often to save a large proportion of the crop; if the bunches
can be covered with a shingle, they will keep fresher much longer. The
fresher the baits, and the more thoroughly the baiting is done, the more
cut-worms one can destroy. However, it may sometimes happen that a
sufficient quantity of such green succulent plants cannot be obtained
early enough in the season in some localities. In this case, and we are
not sure but in all cases, the poisoned bran mash can be used to the
best advantage. It is easily made and applied at any time, is not
expensive, and thus far the results show that it is a very attractive
and effective bait. A tablespoonful can be quickly dropped around the
base of each cabbage or tomato plant; small amounts may be easily
scattered along the rows of onions and turnips, or a little dropped on a
hill of corn or cucumbers.
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