Biology Reference
In-Depth Information
Arge nigripes
(Retzius in Degeer) (
938-939
)
Widely distributed on rose (
Rosa
) and sometimes a pest
of cultivated bushes. Oviposition occurs in the leaf
margins, close to the tips of the main serrations, the
position of each egg being indicated by a distinct
swelling. The larvae feed gregariously from late May
onwards, and often cause noticeable defoliation.
Individuals complete their development in about a
month, each then pupating on the ground in a double-
walled cocoon; there are one or two generations
annually. Larvae (up to 30 mm long) are greenish and
translucent, the body bearing numerous small, mainly
black, verrucae; unlike
Arge ochropus
and
A. pagana
,
there are seven pairs of abdominal prolegs. Adults
(9-11 mm long) are mainly black; they occur in April
and May, with members of a second generation
appearing in July or early August.
Arge ustulata
(Linnaeus) (
940
)
A widely distributed and often common species on birch
(
Betula
) and willow (
Salix
), including ornamentals.
Larvae (up to 22 mm long) are dark green and shiny,
with a pair of white lines down the back; there are
numerous pairs of black verrucae on the body, those on
the thorax being largest and most conspicuous. Larvae
occur from July to September or October. They feed
along the edge of the leaves and cause noticeable, but
usually only minor, defoliation. Adults (10-11 mm long)
are bronzy black with yellowish wings.
938
939
938
Arge nigripes
egg pouches in leaf of
Rosa
.
939
Larva of
Arge nigripes
.
940
940
Larva of
Arge ustulata
.
Search WWH ::
Custom Search