Agriculture Reference
In-Depth Information
Fig. 239
A clover weevil,
Sitona hispidulus
(xl2).
Fig. 238
Pea & bean weevil,
Sitona lineatus
(xl2).
ported in eastern Europe than in the British
Isles; attacks tend to be of greatest significance
under dry conditions. The adults (8-12mm long)
are reddish-brown, with a pale margin to the
thorax and hind-most parts of the elytra. In
outline, they are elongate with a relatively nar-
row thorax; also, the elytra taper noticeably
posteriorly.
Tanymecus palliatus
(F.)
Beet leaf weevil
This weevil is a minor pest of sugar beet. The
adults notch the edges of the cotyledons and
young leaves but damage is more often re-
ORDER DIPTERA (TRUE FLIES)
Family TIPULIDAE (crane flies)
Nephrotoma appendiculata
(Pierre)
Spotted crane fly
random on the soil. The eggs hatch in the early
autumn, after a period of summer diapause. The
larvae then feed on the subterranean parts of
various plants before overwintering. Larvae re-
sume feeding in the early spring and most com-
plete their development by the middle of April.
Pupation takes place in the soil, and the pupa
wriggles to the surface shortly before the adult
emerges.
This crane fly is a generally common but minor
pest, and is usually of most significance in gardens
and allotments. The larvae (known as 'leather-
jackets') cause damage to the roots of grasses,
especially in the early spring when patches of
dead or dying plants may appear. The larvae also
attack the roots, stolons and underground parts of
stems of many other plants, including various
ornamentals, soft-fruit crops and vegetables.
DESCRIPTION
Adult
up to 20 mm long, mainly black, yellow
and golden-yellow;
head
with a distinct black tri-
angular mark;
prescutum
with three conspicuous
black markings
(Fig. 240);
wings
up to 15 mm
long and clear, apart from a pale yellow or light
brown stigma.
Egg
0.8 x 0.4 mm, oval and black
BIOLOGY
Adults of this often abundant crane fly are most
numerous in May, and eggs are then deposited at
