Agriculture Reference
In-Depth Information
Family OECOPHORIDAE
Agonopterix nervosa
(Haworth)
Carrot & parsnip flat-body moth
in the autumn and then hibernate. They reap-
pear in the following March or April, and eggs
are then laid on the leaves of parsnip and other
hosts.
Infestations of this generally common species
occur on various umbelliferous plants including,
occasionally, cultivated carrot and parsnip. Dam-
age caused is of little or no importance.
DESCRIPTION
Adult
25-27 mm wingspan;
thorax
pale brown
with three short black longitudinal lines
anteriorly;
forewings
mainly pale brown, suf-
fused with black and ochreous-white, and pat-
terned with black streaks
(Plate He);
hindwings
ochreous-white to greyish.
Larva
up to 25 mm
long;
body
dark bluish-grey above and ochreous
to brownish-yellow laterally and below;
pinacula
black, shiny and prominent;
head and pro-
thoracic plate
black and shiny
(Plate llf).
BIOLOGY
Adults occur in August and then hibernate. They
reappear in the following spring and deposit eggs
on the leaves of host plants. Larvae feed on the
flower heads in June and July, surrounded by
silken webbing; they also bore into the stems and
petioles. Pupation occurs in the pith of plant
stems.
Family GELECHIIDAE
Phthorimaea operculella
(Zeller)
Potato moth
DESCRIPTION
Adult
21-24 mm wingspan;
forewings
mainly
brown with slightly dusky veins;
hindwings
pale
but darkened apically.
Larva
up to 20 mm long;
body
blue-black, marked with orange laterally
and intersegmentally;
pinacula
distinct black
and white-edged;
head and prothoracic plate
black.
Pupa
10-12 mm long, brown and shiny.
This insect is mainly a pest of the subtropics.
However, infestations also occur in temperate
regions. The larvae burrow into potato leaves,
stems and tubers and are particularly damaging
to tubers in store. Damaged potato tubers are
often invaded by fungi and mites, and the re-
maining tissue then rapidly decomposes. Dam-
age is also recorded on other members of the
Solanaceae, including aubergine and tomato. On
tomato, significant damage may result when
the larvae bore within the leaves, stems and de-
veloping fruits. This pest is not established in the
British Isles, although it is known to occur occa-
sionally in association with imported produce.
Depressaria pastinacella
(Duponchel)
Parsnip moth
This moth is a widespread and often common,
but minor, pest of cultivated parsnip. The larvae
also feed on certain wild umbelliferous plants,
including
Heracleum sphondylium
and
Pastinaca
sativa.
The larvae, which damage the stalks and
flower heads, weaken host plants and reduce
crop yields and quality.
BIOLOGY
Adults tend to be active from April to October.
Under suitable conditions, there may be six if not
more overlapping generations annually (10°C
being the threshold for larval development).
Adults usually lay their eggs in cracks or crevices
on potato tubers, tomato stems and so on. The
eggs usually hatch within a few days. Larvae then
bore into the plant tissue to form silk-lined gal-
leries from which, as development proceeds,
frass is ejected. Larvae are usually fully fed in
BIOLOGY
Larvae, often known as 'parsnip webworms',
feed from June onwards. At first, they attack the
aerial parts of host plants, including the flower
heads and seed capsules, and produce tough
strands of silk amongst which they shelter. Later,
the larvae bore into the plant stems, usually to-
wards the base of the leaves. Fully fed larvae
pupate in the stalks of host plants. Adults appear
