Agriculture Reference
In-Depth Information
BIOLOGY
Adults appear in the spring and eggs are then
deposited in the upper surface of leaves of host
plants, usually close to the mid-rib. Each larva
burrows within the leaf tissue and eventually
pupates at the end of the mine; feeding may also
extend into the stems but never into the roots. In
northern Europe, there is normally just one gen-
eration annually and larvae complete their feed-
ing and pupate in the spring. In warmer regions
and in forcing sheds, however, feeding is com-
pleted more rapidly and there may be several
generations annually. When chicory plants are
lifted in the autumn and cut for forcing, larvae in
the bases of the plants transfer to the developing
blanched heads, where they will continue to feed
throughout the winter.
summer. Eggs are laid in the base of the stems of
host plants. After egg hatch, the larvae mine just
below the epidermis. At first, they bore upwards
for several centimetres; later, they burrow down-
wards, each forming an irregular feeding gallery.
The mines, usually several in each infested plant,
often extend below soil level. Pupation occurs in
the mine, immediately below the epidermis.
DESCRIPTION
Adult
shiny black;
wings
2.2-3.0mm long.
Larva
up to 5 mm long, creamish-white;
cephalo-
pharyngeal skeleton
with dorsal elements (dorsal
cornu) (see Fig. 107) divided into two;
mouth-
hooks
with long axis set more or less obliquely to
rest of mouthparts (cf. asparagus fly,
Platyparea
poeciloptera,
p. 190);
posterior spiracles
each
with about 16 pores and borne on broad, raised
processes.
Puparium
4 mm long, brown, some-
what flattened;
posterior spiracles
borne on
broad, raised processes.
DESCRIPTION
Adult
2.5-3.0mm long, black, stout-bodied;
ab-
domen
distinctly shiny;
antennae
separated by a
prominent facial keel;
wings
1.9-2.3 mm long.
Larva
up to 6 mm long, whitish-yellow;
posterior
spiracles
each borne on a distinct stalk and with
about 10 large pores;
cephalopharyngeal skeleton
with dorsal elements (dorsal cornu) (see Fig.
107) divided into two;
mouth-hooks
each with a
single prominent tooth (cf.
Napomyza cichorii,
p. 190).
Puparium
3.5mm long, pale yellow;
posterior spiracles
each borne on a stalk.
Phytomyza nigra
Meigen
This widespread and generally common leaf
miner is a minor pest of barley, oats, rye and
wheat; it is also associated with various grasses.
Damage is usually insignificant and restricted to
the loss of photosynthetic tissue.
BIOLOGY
Larvae feed within the leaves of various cereals
and grasses to form long, narrow, whitish mines.
Pupation occurs in the mine, with the anterior
spiracles of the puparium protruding through the
upper epidermis. There are several generations
annually, and larvae occur from early spring to
late autumn.
Ophiomyia simplex
(Loew)
larva =
Asparagus miner
This fly is well established in the main asparagus-
growing areas of continental Europe, where it is
sometimes considered an important pest; how-
ever, observations in America and elsewhere
suggest that this pest actually has little or no
detrimental effect on crop yields. Larval feeding
causes the outer tissue of stems to split; also,
infested plants often turn yellow and wilt.
Larval-damaged tissue may be invaded by patho-
genic organisms, so that affected stems rot and
eventually break off.
DESCRIPTION
Adult
mainly greyish to black;
legs
black with
yellow knees;
squamae
yellowish-grey;
wings
2.3-2.6 mm long, the costal vein extending to
vein R
4+
5
(see
Fig. 260b). Larva
whitish-yellow;
anterior spiracles
each with up to 18 pores and
borne on a relatively long, outwardly curved
stalk (cf.
Phytomyza fuscula,
p. 193);
posterior
spiracles
each with 10-13 pores and borne on a
BIOLOGY
Adults appear from early June to mid-July, with
a partial second generation emerging in the late
