Agriculture Reference
In-Depth Information
Family EPERMENIIDAE
Epermenia chaerophyllella
(Goeze)
P. padus, P. spinosa
and
Salix alba)
are collec-
tively known as 'small ermine moths'.
BIOLOGY
Moths are active in July and August. Eggs are
laid on shoots and spurs in long, oval or elongate,
raft-like batches of up to 80 or more and then
coated with a protective secretion that hardens
soon afterwards. The eggs hatch in the autumn.
The larvae then congregate and overwinter be-
tween the remains of the egg raft and the under-
lying bark. In the early spring, the larvae invade
the opening buds; later, they mine gregariously
within the expanded leaves to form large
blotches. Second-instar larvae vacate the mines
to feed externally in communal webs, attacking
both leaves and blossom trusses. Infested shoots
and branches may become coated in webbing.
The larvae are fully fed in June. They then pu-
pate in white, opaque cocoons spun in groups
within the web. Adults appear about 2 weeks
later.
This moth is a widespread but usually minor pest
of garden-grown or allotment-grown parsnip; in-
festations also occur on carrot. Leaves are grazed
from below; the upper surface remains intact but
turns brown to give the appearance of an ex-
tended blotch; attacks commence close to the
petiole and, particularly on lower leaflets, may
spread over most if not all of the lamina. Heavy
infestations reduce the vigour of plants (cf. infes-
tations of celery fly,
Euleia heraclei,
p. 179).
BIOLOGY
Adults appear in April or early May. They de-
posit eggs on the leaves of host plants, and first-
generation larvae occur from June onwards. The
larvae usually commence feeding by mining the
leaves but they soon occur externally, to feed
gregariously amongst strands of silk; they expel
large quantities of black frass
(Plate lie).
Fully/
grown individuals pupate on the ground amongst
debris, each in a flimsy, net-like cocoon. A sec-
ond generation of adults appears in July and
August. Larvae of this generation complete their
development in September or early October.
DESCRIPTION
Adult
18-22 mm wingspan;
forewings
white with
a characteristic pattern of small white spots;
hindwings
grey
(Fig. 275). Egg
flat, dark
purplish-grey and laid in a large batch.
Larva
up to 20 mm long; body dirty yellowish-grey;
head, pinacula and dorsal plates
black
(Fig.
276). Young larva
mainly yellowish-white;
head and prothoracic plate
brown.
Pupa
10 mm
long; mainly yellow but head, thorax, wing cases
and tip of abdomen darker;
penultimate segment
with a distinct ventral hump;
cremaster
with six
long filaments.
Fig. 276
Larva of apple small ermine moth,
Yponomeuta malinellus
(x4): (a) arrangement of
crochets on an abdominal proleg (further enlarged).
Fig. 275
Apple small ermine moth,
Yponomeuta
malinellus
(x4).
