Agriculture Reference
In-Depth Information
Fig. 240
Head and thorax of
Nephrotoma.
Fig. 242
Outline of the anal segment of
leatherjackets: (a)
Nephrotoma appendiculata;
(b)
Tipula paludosa.
are often reported on reseeded grassland and
on cereal and vegetable crops which follow
ploughed-up infested grassland; they also occur
on strawberry, on various outdoor ornamentals
(including bedding plants) and on containerized
plants grown in plastic tunnels and under other
protective structures.
Fig. 241
Crane fly eggs: (a)
Nephrotoma
appendiculata;
(b)
Tipula paludosa
(x20).
(Fig. 241a). Larva
up to 30 mm long, greyish-
brown;
prothoracic segment
with a pair of small
humps dorsally;
posterior papillae
distinctive -
the lateral pair on the spiracular disc longer than
the dorsal pair and the anal lobes all rounded (cf.
common crane fly,
Tipula paludosa,
below)
(Fig.
242a).
BIOLOGY
Unlike the following species,
Tipula paludosa
is
univoltine, most adults occurring in late August
and September. Eggs are laid at random in the
soil, each female depositing up to 300 or more.
The eggs hatch in approximately 2 weeks but
they are very susceptible to desiccation and re-
quire high humidity to survive. The larvae
feed from autumn onwards and are usually fully
grown by the following summer. They then pu-
pate in the soil, and adults emerge about 3 weeks
later. Gravid females do not fly, so that eggs tend
to be laid close to where the adults emerged from
the pupa and mated; consequently, populations
of the pest can quickly build up in suitable sites
(cf.
T. oleracea,
below).
Tipula paludosa
Meigen
A common crane fly
This well-known pest is often abundant in wet
grassland and pastures. The soil-inhabiting lar-
vae (known as 'leatherjackets') often attack the
roots and germinating seeds of cereals planted in
recently ploughed-up grassland, and can cause
considerable damage. At night, they also come
to the surface and may then sever or otherwise
damage the basal parts of stems; leaves in con-
tact with the soil may also be holed or shredded.
Damage is particularly severe in spring, when
attacked plants turn yellow, wilt or die; dead or
dying plants frequently occur in patches. Attacks
DESCRIPTION
Adult
17-25 mm long, grey with a yellowish-
red or brownish tinge and indistinct longitudinal
