Agriculture Reference
In-Depth Information
Fig. 209
Larva of pollen beetle.
Meligethes aeneus
(x!6).
Fig. 208
Pollen beetle,
Meligethes aeneus
(x25).
The larvae develop within the opening buds and
flowers for 3-4 weeks, passing through just two
instars. Fully grown individuals then drop to the
ground where they eventually pupate, each in a
small earthen cell. New adults emerge in
July.
They then migrate to open flowers of various
kinds of plant, where they feed on pollen. They
then seek suitable overwintering quarters in the
soil. There is only one generation a year.
pest in the warmer parts of continental Europe.
Compared with
M. aeneus,
the adults are slightly
larger, the legs paler and the elytra more
coarsely, but less densely, punctured; larvae are
also larger (up to 5 mm long when fully grown)
with, in addition to detailed microscopical dif-
ferences, the anal plate more strongly indented
posteriorly.
Family CRYPTOPHAGIDAE
(mould beetles)
Atomaria linearis
Stephens
Pygmy mangold beetle
DESCRIPTION
Adult
1.5-2.7 mm long, mainly black, with a
metallic bronzy-green tinge;
elytra
finely punc-
tured
(Fig. 208). Egg
0.8 x 6.3 mm, elongate
with rounded ends, translucent-whitish.
Larva
up to 4 mm long;
body
creamish-white, with dark
brown to black thoracic and abdominal plates;
head
black;
legs
blackish
(Fig. 209);
anal plate
slightly indented posteriorly (cf.
Meligethes
viridescens,
below).
This locally abundant pest is associated mainly
with mangold and sugar beet; adults also occur
on red beet and spinach but attacks on these
crops are rarely serious. In the British Isles,
infestations are most frequent in southeastern
England. The adult beetles bite into the roots
and hypocotyl of plants, producing characteristic
pits that soon turn black (see also damage caused
by blind springtails,
Onychiurus
spp., p. 87).
Heavy attacks on seedlings may lead to signifi-
cant loss of plants, whereas those on the roots of
older plants may result in distortion. Adults also
feed on furled leaves at the heart of young plants,
Meligethes viridescens
(F.)
Bronzed pollen beetle
This pollen beetle is essentially similar to
Meligethes aeneus
(above) but, in the British
Isles, is usually far less numerous and also occurs
slightly later in the season. It is a more significant
