Agriculture Reference
In-Depth Information
DESCRIPTION
Adult
up to 5 mm long, dark grey;
legs
black.
Larva
up to 7 mm long, yellowish-white;
anterior spiracles
prominent, frilly-edged, with
up to 20 lobes;
posterior spiracles
borne on
distinct tubercles;
posterior papillae
very small
or absent (cf. wheat bulb fly,
Delia coarctata,
p. 197).
ORDER LEPIDOPTERA (BUTTERFLIES AND MOTHS)
Family HEPIALIDAE (swift moths)
Hepialus humuli
(L.)
Ghost swift moth
Hepialus lupulinus
(L.)
Garden swift moth
This pest is widespread and common on a wide
range of crops, particularly those grown in re-
cently ploughed grassland and those in weedy
sites. The larvae attack the roots and also bore
into bulbs, corms and tubers. Infestations are
often noted on carrot, hop, lettuce, potato and
strawberry, and on many ornamental plants;
bean, beet, cereals, parsnip and various other
crops are also attacked. Damage occurs mainly
from autumn to early spring.
This widely distributed, polyphagous pest is as-
sociated mainly with permanent grassland and
lawns but can also damage a wide range of agri-
cultural and horticultural crops planted in re-
cently broken-up grassland or pasture. The
soil-inhabiting larvae attack the subterranean
parts of plants; particularly severe damage is
caused in the second year of larval development.
BIOLOGY
Adults are active at dusk, mainly in June and
July. The females lay many hundreds of eggs,
which they drop at random whilst skimming over
grassland. The eggs hatch in approximately 3
weeks. The larvae feed from late summer or
early autumn onwards, constructing silken tun-
nels in the soil, into which they often retreat
when disturbed. Larval development is slow and
is usually not completed until after the second
winter. Individuals then pupate in silken co-
coons. Adults emerge about 3 weeks later, the
pupae first working their way to the soil surface.
BIOLOGY
Adults occur mainly in May and June. They are
active at dusk and may then be seen flying low
over fields and gardens. Eggs are broadcast ran-
domly by the females whilst in flight, each depos-
iting about 300. The eggs hatch approximately
2-3 weeks later. Larvae feed indiscriminately on
the subterranean parts of plants. Each larva
forms a silk-lined burrow in the soil, down which
it retreats when disturbed. Larvae develop rela-
tively slowly and usually do not become fully
grown until the following spring. Pupation oc-
curs in a flimsy cocoon several centimetres below
the surface. The adult usually emerges about 6
weeks later, after the pupa has wriggled out of its
cocoon and made its way to the surface of the
ground.
DESCRIPTION
Adult female
50-70 mm wingspan;
forewings
parchment-like, yellowish-ochreous, marked
with orange
(Plate 10c);
hindwings
greyish-
brown.
Adult male
45-50 mm wingspan;
wings
silvery-white.
Egg
0.7 x 0.5 mm; white when
laid but soon turning black.
Larva
up to 50 mm
long;
body
whitish, robust and relatively opaque;
pinacula
dark brown and prominent;
head and
prothoracic plate
reddish-brown
(Plate lOd)
(cf
.
Hepialus lupulinus,
below).
DESCRIPTION
Adult
25-40 mm wingspan, female usually larger
and stouter-bodied than male;
thorax
with a fin-
like tuft of hairs;
forewings
yellowish-brown,
more or less marked with white;
hindwings
yellowish-grey.
Egg
0.5-0.6 mm across, white
when laid but soon turning black and
