Multitudes of men have had plum-trees, and every year, for ten years,
have seen the fruit promise fair at first and then prematurely drop,
without knowing the reason. Even well-informed men have said to us
that it arose from some defect in the _tree_, from too much _gum_,
from a worm at the _root_, etc.
The plum-tree is very hardy; is less subject to disease than most
fruit-trees; its fruit is highly prized; and the varieties of it are
numerous and many of them delicious. By a proper selection of trees a
succession of fruit may be had from July to November. The trees are
usually sure and enormous bearers, every year. With so many good
qualities the cultivation of the plum is well-nigh prohibited, as a
garden or orchard fruit, by the valor of one little bug!
The _Curculio_ (a very hardy fellow, with a constitution yet
unimpaired by such a name as _Rhynchœnus Nenuphar_!) is a small
beetle, about a quarter of an inch long, which attacks the plums
almost as soon as the fruit has set. They seek this, and almost all
smooth-skinned fruits, as a place of deposit for their eggs. Many of
the facts which we shall narrate, were mentioned to us by Mr. Payne of
Madison, who has closely and curiously observed this depredator.
An incision is first made, of semicircular form, by a little rostra or
lancet which he carries in his head for this very purpose. After the
opening is made, the curculio deposits an egg therein; then changing
positions again, it carefully, with its fore legs, secures the egg in
its _nidus_, and pats the skin under the edge of which its treasure is
hidden, with repeated and careful efforts of its feet. Where fruit
abounds it deposits, usually, but one to a plum. But we have had
trees, just beginning to bear, whose few plums were scarified all
over.
The egg hatches to a worm, and this feeds on the plum, causing it
prematurely to fall; the insect issuing from it, enters the ground, to
undergo its transformations, and soon to reappear, a beetle, ready for
fresh mischief-making propagation.
The climate of the West is entirely glorious for all manner of
insects. They can put the East to shame in the matter of aphides,
cockroaches, cutworms, army and wire-worms, curculios, peach-worms,
grubs, etc., etc. There are many questions relating to the history of
insects, about which eastern writers are in doubt, not at all doubtful
with us.
1. Do the larvæ remain in the ground all the residue of the summer,
and come forth only in the ensuing spring? In cold latitudes it may be
so. Harris says, that they undergo their transformation in twenty
days. Downing admits this of a few stragglers. But the main supply of
bugs, he thinks, remains all summer and until spring, in the ground.
But with us the curculio is not exclusively an early summer insect. It
is found, in its appropriate haunts, through the whole warm season.
Mr. Payne put plums containing the worms into a glass, and in eleven
days obtained full-grown curculios. In cool regions they probably have
but an annual generation; but in warm and long summers, in the West,
they reproduce often in each season.
2. The mode of ascent has been a matter of doubt. J. J. Thomas, in the
_Fruit Culturist_ says: “It has the power of using its wings in
flying; but whether it crawls up the tree or ascends by flight,
appears not to be certainly ascertained.”
Downing admits that it flies, but says, “How far this insect flies is
yet a disputed point, some cultivators affirming that it scarcely goes
further than a single tree, and others-believing that it flies over a
whole neighborhood.”
Kenrick says: “They crawl up trees,” and he quotes an author as
saying: “That of two trees standing so near each other as to touch,
the fruit of one has been destroyed and the other has escaped; so
little and so reluctantly do these insects incline to use their
wings.” Dr. James Tilton says, in the “Domestic Encyclopedia,” that
“they appear very reluctant to use their wings, and perhaps never
employ them but when necessity compels them to migrate.”
It is true that the curculio, in cold and chilly weather, is
disinclined to fly; but give it a right murderously hot day, and
“McGregor’s on his native heath again.” Just before a thunder storm,
in summer, in a still, sultry, sweltering day, they may be seen flying
among the trees as blithely as any house-fly; alighting on your arm,
or hand, and springing off again as nimbly as a flea.
All remedies founded on the idea of their crawling preferences will be
signal failures. Troughs about trees, bats of wool, bandages of all
kinds about the trunk to impede the ascent will be found as useful as
would high fences to keep crows from a cornfield, or birds from the
garden.
All remedies for this pest succeed to a charm where the curculio does
not abound; and almost every one of them fails in places really
infested them.
In cities, and in country places which are far removed from all
orchards or gardens, the crops may be saved. It is not difficult to
defend a tree against all the curculios that are _bred upon it_.
Pavements; hard-rolled gravel; gathering up, daily, the fallen plums
and destroying them; the application of salt, and many other remedies
may succeed where the curculio from other gardens or orchards cannot
easily migrate to supply the trees with a fresh brood. Trees in
cities, and in retired places, on this account, often bear
plenteously.
But of what use is it to destroy five hundred larvæ, if twice that
number of emigrants, from some other quarter, are anxious, the next
spring, to _squat_ upon your trees, or to _enter_ them, in land-office
style, most nefariously? All remedies founded on the destruction of
the larvæ will be totally useless if your trees can be reached from
some infected point abroad, as we have found to our sorrow. In our own
experience, and in that of other amateur-cultivators of fruit, the
pavement, salt, and all have been “love’s labor lost.” But in the
experience of others, in climates where the curculio does not abound,
or in secluded situations, they have proved effectual.
The remedies to be employed, in ordinary cases, must be such as will
constantly molest the insect at his work. Inclosures, in which swine
root, and rub against the trees; lanes, where cattle resort, to rub
off their hair in spring, to shade themselves in summer—these are the
best situations. In yards and gardens plum-trees should be placed upon
the most frequented paths; close to the well, by the kitchen door,
near the wood-house, so that, as often as possible, they may be jarred
in passing and repassing.
Where a few trees stand apart in the garden, it is said that, daily,
morning and evening, by spreading a sheet under them, and giving the
tree a sudden and violent blow with a mallet, the insects will drop
and may then be gathered and destroyed. This should be performed while
it is cool, as then, only, the curculio is somewhat torpid. If this
course is pursued, a block should be put upon the tree, to receive the
stroke, with a bit of carpet or some soft pad to it, that the bark may
not be injured. A white sheet should be spread under the tree to catch
the falling robber.
A few trees will suffice for a private family, and the fruit must be
earned by careful watchfulness. Those who are too indolent, or
careless, or indifferent to the luxury to bestow the requisite
attention through the months of May and June, may spare themselves the
trouble of planting plum-trees. Plum _orchards_ are not to be thought
of.
Although the curculio chiefly delights in the plum, it scruples at no
fruit. It may be found upon peaches, cherries, nectarines, apricots,
gooseberries and currants.