Agriculture Reference
In-Depth Information
pale purplish-brown;
pinacula
brown;
head and
prothoracic plate
brown with darker markings.
Chrysoteuchia culmella
(L.)
Garden grass veneer moth
This generally abundant species sometimes
causes severe damage in permanent grassland.
Attacked plants are severed at or below ground
level, damage being caused both to the leaves
and the root system. Large patches of dead grass
occur in heavily infested sites, and damage may
extend over several hectares.
BIOLOGY
Adults occur in June and July. They fly mainly at
dusk but, if disturbed during the daytime, they fly
away erratically to settle again a short distance
,away, typically head downwards on grass stems.
Eggs are dropped at random onto the soil in
grassy situations; they hatch shortly afterwards.
The larvae. attack the base of grass stems; the
larvae also;,giaze on the leaves. They shelter in
the soil within the root system, typically adopting
a C-shaped posture; unlike various closely re-
lated species (e.g.
Agriphila straminella,
p. 223),
they do not form silken galleries Individuals are
usually fully fed by the autumn. They then
overwinter and pupate in the late spring.
^Sli# (a)
Fig. 300
Anterior part of larva of garden grass
veneer moth,
Chrysoteuchia culmella
(xlO):
(a) arrangement of crochets on an abdominal
proleg (further enlarged).
brassica crops, including broccoli, Brussels
sprout, cabbage, cauliflower and turnip. The lar-
vae, sheltered by masses of fine webbing in which
their frass accumulates, also invade the heads of
broccoli and cabbages; such plants are often
rendered unmarketable. Although rarely trou-
blesome on field crops, infestations can be of
significance in allotments, market gardens and
on garden vegetable plots.
BIOLOGY
Adults of the first generation occur in May and
June. Eggs are then laid in small batches on the
leaves of host plants. They hatch about 10 days
later. The larvae feed for about 3 weeks, often
webbing young leaves together; there are four
larval instars. Pupation takes place in the soil in
strong silken cocoons formed a few centimetres
below the surface. Adults emerge in August and
September. Second-generation larvae feed dur-
ing the autumn, and complete their development
before the onset of winter. They then enter the
soil where they overwinter; they eventually pu-
pate in the spring. Under favourable conditions
there may be a partial third generation.
DESCRIPTION
Adult
20-24 mm wingspan;
forewings
yellowish-
brown, marked with black and with a pale, dis-
tinctly bent subterminal line
(Plate 13a);
hindwings
brownish-grey.
Larva
up to 15 mm
long;
body
yellowish-white to dirty greenish-
white;
pinacula
large and shiny (but pale and
often indistinct), each bearing a relatively
long, stout, black seta;
spiracles
small and jet
black
(Fig. 300);
head
chestnut-brown;
prothor-
acic plate and anal plate
yellowish-brown to
brownish-black
(Plate 13b).
Evergestis forficalis
(L.)
Garden pebble moth
DESCRIPTION
Adult
25-27 mm wingspan;
forewings
brownish-
white, with brown and blackish markings
(Plate
Infestations of this often common but usually
minor pest occur on the leaves of various
