Agriculture Reference
In-Depth Information
attacks typically occur on crops that follow a
grass ley. The larvae, which transfer from the
ploughed-in grass, bite into the base of the
shoots of the young cereal plants; the centre
shoots may then turn yellow. Damaged shoots
usually have a distinct, often ragged, hole at the
base; they may also be severed. Unlike certain
other ley pests (e.g. frit fly,
Oscinella frit,
p. 195;
wheat flea beetle,
Crepidodera ferruginea,
p.
141) the larvae do not enter the shoot but may be
found (although usually with difficulty) in the
surrounding soil. In the British Isles, infestations
occur mainly in eastern England.
Fig. 200
Pronotum of turnip mud beetle,
Helophorus rufipes.
eggs hatch in the autumn and the larvae then
attack suitable host plants. The larvae feed
mainly within the stems and roots, and remain
active throughout the winter. They are fully
grown by March or early April. Each then pu-
pates in a small earthen cell a short distance
below the soil surface. There is just one genera-
tion annually.
BIOLOGY
Adults occur throughout the spring and summer,
but eggs are not laid until the autumn. The larvae
feed from November onwards and complete
their development in the following spring. Pupa-
tion usually occurs in April or May, and adults
usually appear from May onwards.
DESCRIPTION
Adult
4-5 mm long, mainly dirty yellow, marked
irregularly with black;
pronotum
with an irregu-
lar, wart-like sculpturing
(Fig. 200);
elytra
promi-
nently ridged longitudinally.
Helophorus rufipes
is the slightly larger species and the anterior
(humeral) angles of the elytra are dentate - they
are rounded in
H. porculus.
Larva
up to 8 mm
long;
body
creamish-white, with brownish or
blackish dorsal plates on the thoracic and ab-
dominal segments;
anal cerci
present.
DESCRIPTION
Adult
3-4 mm long, dirty yellow, marked
with black;
pronotum
hood-like and ridged
longitudinally;
elytra
prominently ridged longi-
tudinally.
Larva
up to 7 mm long;
body
mainly
white, with brownish or blackish dorsal plates;
head
dark brown;
thoracic legs
short;
anal cerci
moderately long.
Helophorus porculus
Bedel;
H.
rufipes
(Bosc d'Antic)
Turnip mud beetles
Family SILPHIDAE (burying beetles)
Aclypea opaca
(L.)
Beet carrion beetle
Both species of turnip mud beetle are widely
distributed but minor and sporadic pests of tur-
nip and certain other brassicas (cabbage, kale
and swede); they may also attack other plants,
including beans and lettuce. Adults remove sec-
tions of tissue from within or around the edges of
leaves. The larvae more frequently tunnel in the
roots and stems, causing plants to rot.
The beet carrion beetle is associated mainly with
members of the Chenopodiaceae and was for-
merly an important pest of mangold and sugar
beet crops, especially in continental Europe.
Attacks have also been noted on various other
plants, including cereals, potatoes and vegetable
brassicas, smooth-edged holes being made in the
leaves. If populations are large, adults and larvae
cause significant damage to the foliage of beet
seedlings, especially on backward, slowly germi-
BIOLOGY
Adults occur from June onwards, and eggs are
deposited in the soil during July and August. The
