Biology Reference
In-Depth Information
297
298
297
Adult of
Plagiodera versicolora
.
298
Young larvae of
Plagiodera versicolora
.
299
Plagiodera versicolora
(Laicharting) (
297-299
)
This species infests poplar (
Populus
) and willow (
Salix
)
in various parts of Europe. Adults occur mainly from
April or May to September, depositing eggs in groups of
10-30 on the underside of the leaves. The eggs hatch in
about a week. Larvae then feed in groups on the
underside of the leaves. They remove the lower tissue,
the upper surface remaining intact but turning brown.
Young larvae are mainly black and shiny; older
individuals, that feed on either the upper or the lower
surface of leaves, are lighter in colour but have the body
darkened by shiny black verrucae and plates. There are
two main generations annually, larvae occurring from
May onwards, but the developmental stages tend to
overlap. The ladybird-like adults are 3.0-4.5 mm long,
somewhat flattened, and metallic blue or blue-green,
with irregularly punctured elytra and black legs. They
also browse on the foliage of host plants but
damage, although unsightly on ornamentals, is usually
insignificant. Adults overwinter under loose bark,
amongst dry leaves and in other shelter.
299
Older larvae of
Plagiodera versicolora
feeding on leaf of
Salix helvetica
.
300
Podagrica fuscicornis
(Linnaeus) (
300
)
Mallow flea beetle
This species is associated mainly with wild mallows,
including common mallow (
Malva sylvestris
), marsh
mallow (
Althaea officinalis
) and musk mallow
(
M. moschata
). Infestations sometimes also occur
during the summer on ornamental mallows in parks and
gardens, the adults causing extensive damage to the
leaves. Adults are 3-6 mm long, with the head, thorax
and legs pale yellowish red, and the elytra metallic blue
to metallic blue-green.
300
Mallow flea beetle (
Podagrica fuscicornis
) damage to
foliage of
Malva
.
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