Agriculture Reference
In-Depth Information
the overlying tissue eventually collapses to pro-
duce obvious, irregular scars which open out as
the root grows (cf. carrot fly,
Psila rosae,
p. 181).
Such damage tends to predispose the roots to
invasion by pathogens, especially in wet condi-
tions, and is a particular problem on crops in
store. Although well established in parts of con-
tinental Europe, including Germany, the Nether-
lands and Switzerland, in the British Isles, where
it was first reported (in East Anglia) in 1974, it is
rare and not of pest status.
to those formed by the black chicory fly,
Ophiomyia pinguis
(below). In addition, mines
in the roots, and within the blanched heads, lead
to distortion, stunting and weakening of host
plants. Heavy infestations result in considerable
crop losses.
BIOLOGY
Adults of the first generation occur in May and
June. Eggs are laid in the mid-rib of chicory or
endive. The larvae form mines which extend
deeply into the plant tissue, including the roots.
At summer temperatures, development is rela-
tively rapid, and pupation takes place within
about a month. A second generation of adults
appears in August, and these produce the gen-
eration of larvae that invade winter-forced crops.
Although normally bivoltine, there may be a par-
tial third generation if conditions are favourable.
BIOLOGY
Eggs are laid in the leaves or stems of carrot
plants. The adult females also make pale,
rounded feeding punctures in the foliage, each
c.
0.5 mm in diameter. After eggs have hatched,
the larvae mine downwards within the mid-rib,
petiole and stem; except in mature plants, the
larvae also invade the roots. Pupation takes
place within the mine. Adults occur from May to
June, and from August to September; in some
situations, there may be a partial third genera-
tion in October. The winter is passed in the pupal
stage.
DESCRIPTION
Adult
greyish to blackish, with parts of the
thorax yellow;
legs
black with yellow knees;
wings
2.7-3.5 mm long.
Larva
5 mm long, whit-
ish;
posterior spiracles
each with a double row of
minute pores;
mouth-hooks
with main axis set
more or less at right-angles to rest of mouthparts;
posterior spiracles
each with a double row of
about 22 minute pores (cf. black chicory fly,
Ophiomyia pinguis,
below).
DESCRIPTION
Adult
mainly grey or black;
wings
2.7-3.1 mm
long, the genus differing from
Phytomyza
(q.v.) by the addition of another cross-vein;
legs
black with yellow knees.
Larva
up to 6 mm
long, white;
mouth-hooks
with main axis set
more or less at right-angles to rest of mouthparts,
and each with several small teeth;
posterior
spiracles
borne on distinct projections and each
with a double row of about 20 minute pores
(cf. carrot fly,
Psila rosae,
p. 181).
Puparium
4.5-5.5 mm long, white, slender;
posterior
spiracles
brownish-black, each borne on a short
projection.
Puparium
4-5 mm
long,
slender,
whitish;
posterior spiracles
blackish-brown.
Ophiomyia pinguis
(Fallen)
Black chicory fly
This insect is an important pest of chicory in
continental Europe, and is particularly numer-
ous in the chicory-growing regions of Belgium,
France, the Netherlands and Switzerland; al-
though not an established pest, it is introduced
occasionally into the British Isles. The larval
mines, which are often reddish tinged, spoil the
appearance of harvested white chicory heads
and, if infestations are heavy, the crop may be
unmarketable. Attacks also occur on endive and
lettuce.
Napomyza cichorii
Spencer
This species is restricted to parts of continental
Europe, including Belgium, France, Italy and the
Netherlands, where it is a locally important pest
of chicory and endive. Larval mines in leaves and
blanched chicory heads cause similar damage
