Biology Reference
In-Depth Information
Family
COSSIDAE
Zeuzera pyrina
(Linnaeus) (
488-490
)
Leopard moth
A sporadically important pest of various trees and
shrubs, including ash (
Fraxinus excelsior
), birch
(
Betula
),
Cotoneaster
, crab-apple (
Malus
), flowering
cherry (
Prunus
), hawthorn (
Crataegus
), honeysuckle
(
Lonicera
), horse chestnut (
Aesculus hippocastanum
),
lilac (
Syringa
), maple (
Acer
),
Rhododendron
and
sycamore (
Acer pseudoplatanus
). Widespread in
mainland Europe; in Britain restricted mainly to the
southern half of England and eastern Wales. Also
introduced into North America.
Large or very large moths. The larvae are wood-borers,
feeding in the trunks and branches of trees and shrubs.
Cossus cossus
(Linnaeus) (
487
)
Goat moth
Infestations of this widely distributed but generally
uncommon, wood-boring species occur in various mature
trees, including ash (
Fraxinus excelsior
), birch (
Betula
),
elm (
Ulmus
), flowering cherry (
Prunus
), oak (
Quercus
)
and willow (
Salix
). The large (70-100 mm wingspan),
dull, greyish-brown moths occur in June and July, and are
sometimes found resting on tree trunks during the
daytime. Eggs are deposited in crevices in the bark,
usually in groups of about fifty. After egg hatch, the
pinkish naked-looking larvae immediately burrow into
the trunks to feed within the sap and heart wood. Larval
development is greatly protracted, lasting up to three or
four years. Fully grown individuals (80-100 mm long)
eventually pupate just below the bark, or in the ground, in
strong, silken cocoons. Larval feeding galleries are very
extensive and the larvae may eventually cause the death
of host trees. Infested trees are characterized by the
presence of large emergence holes in the bark, from
which sap is sometimes exuded. An unpleasant, goat-like
smell is also emitted from the larval galleries.
DESCRIPTION
Adult:
45-65 mm wingspan; wings white and
translucent, with black or blue-black spots; body
similarly coloured and rather velvety; male
considerably smaller than female and with the antennae
strongly bipectinate basally.
Egg:
1 mm long; oval and
pinkish-orange.
Larva:
up to 60 mm long; yellowish,
with prominent black pinacula; head and prothoracic
plate brownish black, the latter with a characteristically
scalloped hind margin; young larvae at first pinkish,
readily distinguished from those of other wood-boring
species by the characteristic prothoracic plate.
Pupa:
25-35 mm long; reddish brown.
LIFE HISTORY
Adults occur in June or July, depositing eggs in groups
in wounds or cracks in the bark of host plants. The newly
emerged larvae initially attack the leaf stalks and major
leaf veins, buds and shoots of host plants. Later, they
then enter the larger twigs and branches to feed in the
heart wood. Larval galleries extend for 40 cm or more, a
larva taking two or three years to complete its
development. Pupation occurs in the feeding gallery in a
slight cocoon into which particles of wood are
incorporated. In early summer the pupa wriggles out of
the cocoon and breaks through the surface of the branch
where it remains protruding after emergence of the adult.
487
DAMAGE
Attacks usually occur in branches, stems or trunks less
than 10 cm in diameter. The presence of a larva is
indicated by the accumulation of frass and particles of
wood which are forced out of the entry holes and, later,
by the withering and die-back of the leaves and shoots.
Infested branches are weakened and may snap off in a
strong wind.
487
Goat moth (
Cossus cossus
) damage to trunk of
Quercus
.
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