Garden Pests in New Zealand: A Popular Manual for Practical Gardeners, Farmers and Schools — John Stuart Mill — John Shaqi
Garden Pests in New Zealand: A Popular Manual for Practical Gardeners, Farmers and Schools
John Stuart Mill · en
BLACK PEACH--APHIS(_Aphis persicæ-niger_).--From early spring, even
before the foliage develops, this aphis may be found heavily infesting
the young, succulent shoots of peach; it also occurs on cherry, plum
and nectarine. The adult insects are black and the immature stages
pale reddish-brown, dull brown, or lemon-yellow. During the winter the
insect lies underground about the roots of the host plant, and thence
migrates to the young growth in spring. At first only wingless forms
are seen, but as the season advances the winged migratory aphides
develop; at that time the foliage is so severely attacked that it
becomes crumpled and functionless (Fig. 9, 1), while the developing
fruit is distorted and rendered useless. The heat of the late summer
destroys the aphides still on the foliage, but sufficient numbers
descend underground for protection, where they live over winter.
GREEN PEACH--APHIS(_Rhophalosiphum persicæ_).--This aphid occurs
on a wide range of plants, including the peach, and, as a rule, is
most abundant during summer and autumn; as the name implies, the
general colour is green, though some individuals are reddish or
brownish-yellow; the wingless forms have black-tipped “cornicles,” and
on the abdomen of the winged insects are dark markings.
BLACK CHERRY--APHIS OR FLY(_Myzus cerasi_).--This aphid has now a
world-wide distribution. In New Zealand it has been found on cherry
and plum, though in other countries its hosts include peaches, red
and black currants, and cruciferous plants, such as common mustard,
shepherd’s purse, etc. This species exudes copious honey-dew, upon
which sooty mould develops, thus rendering fruit unfit for use. The
principal injury, however, is due to the destruction of shoots and
leaves, the latter frequently curling up when the insect clusters in
dense colonies upon the infested plant. The complete life-cycle has
not been followed under New Zealand conditions, but the shiny black
eggs occur on the bark and buds of cherry trees during the winter. In
spring the eggs hatch, and the insects, rapidly reproducing, attack
the young shoots and leaves. Observers in other countries have noted
that there is a summer migration of winged females to cruciferous
plants, where colonies are established, and whence there is a return
migration during the autumn to the original host. The wingless females
are black, with part of the legs yellow, while the young individuals
are pale in colour; the winged females have a green abdomen, from which
arise the black “honey-tubes.” Since all the over-wintering eggs have
hatched by the time the buds open, the insect can be then controlled by
applications of nicotine-sulphate.
[Illustration: FIG. 9.