Biology Reference
In-Depth Information
766
767
766
Larva of common emerald moth (
Hemithea aestivaria
).
767
Common emerald moth (
Hemithea aestivaria
).
Erannis defoliaria
(Clerck) (
763-765
)
Mottled umber moth
A generally common pest of ornamental trees and
shrubs, including birch (
Betula
), elm (
Ulmus
), flowering
cherry (
Prunus
), hazel (
Corylus
), honeysuckle
(
Lonicera
), hornbeam (
Carpinus betulus
), lime (
Tilia
),
oak (
Quercus
), poplar (
Populus
) and rose (
Rosa
); also a
pest of deciduous forest trees and fruit trees. Widely
distributed in Europe; also present in Canada.
DAMAGE
Larvae cause considerable defoliation. Attacks on the
buds and blossoms of trees and shrubs are also of
importance, and complete trusses may be destroyed.
Hemithea aestivaria
(Hübner) (
766-767
)
Common emerald moth
A widely distributed species, the larvae feeding during
the autumn on low-growing plants and then hibernating.
In the spring, the larvae attack the foliage of various
trees and shrubs. Minor damage is then sometimes
caused to nursery plants and garden ornamentals,
including birch (
Betula
), hawthorn (
Crataegus
), lime
(
Tilia
), oak (
Quercus
), rose (
Rosa
) and willow (
Salix
).
Fully grown larvae (
c.
22 mm long) are dull green,
marked with black and reddish brown; the head and first
thoracic segment are distinctly notched, and the body
surface noticeably roughened. The green, angular-
winged adults (24-28 mm wingspan) occur in late June
and July.
DESCRIPTION
Adult female:
wingless; body 10-15 mm long, mottled
with black, yellow and, sometimes, white scales.
Adult
male:
35-38 mm wingspan; fore wings pale yellow to
reddish brown, more or less finely peppered with black,
and often variably decorated with dark cross markings.
Egg:
0.9
0.5 mm; oval, yellowish to greyish; shell
almost smooth.
Larva:
up to 35 mm long; reddish
brown, with yellow or creamy-white areas on the sides
of the first to seventh abdominal segments.
Pupa:
12-14 mm long; dark yellowish brown; cremaster with
a short, bifid tip.
×
LIFE HISTORY
Adults occur from mid-October to mid-January. The
colourful males are sometimes noticed at rest during the
daytime on trees, fences and walls but the wingless
females are rarely seen. Eggs, which are laid in bark
crevices, hatch in early April. The larvae then feed
ravenously, usually resting fully exposed on the leaves
or shoots. They are easily dislodged from the foodplant.
They then remain temporarily suspended by a silken
thread, with the head and thorax bent back at an angle to
the abdomen. In June, fully fed larvae pupate in the soil
a few centimetres below the surface.
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