Agriculture Reference
In-Depth Information
immediately crawls down the bulb and bites its
way in through the base plate. Further develop-
ment occurs within the bulb. Larvae are usually
fully grown by the winter. They pupate in the
spring, usually in the neck of the infested bulbs.
In forcing houses, development of the pest may
be accelerated and adults often emerge as early
as February.
one or several eggs are laid; this oviposition
puncture later becomes surrounded by a sunken
area of rotting tissue. Larvae feed within the
flesh of the infested fruit and, when fully grown,
emerge to pupate in the soil. There are several
generations in a season, the rate of development
(and, hence, number of generations) depending
considerably on temperature. At optimum tem-
peratures of 32°C, development is very rapid, the
life-cycle then being completed in approximately
2 weeks.
DESCRIPTION
Adult 2-14 mm long; body bumblebee-like,
clothed mainly in gingery-brown hairs but hairs
often forming black, grey or reddish crossbands
(Plate 6f). Egg 1.6mm long, elongate-oval,
pearly-white. Larva up to 18 mm long, stout-
bodied, dirty yellowish-white; posterior respira-
tory cone dark brown.
DESCRIPTION
Adult 4-5 mm long; head yellowish; eyes colour-
ful and iridescent; thorax black, marked with
greyish-brown; wings clear, with black veins and
dark spots and orange markings; legs yellowish;
abdomen stubby, orange-yellow and with two
silvery-white crossbands, the female with a dis-
tinct oviscapt. Egg 1mm long, white, elongate
and somewhat banana-shaped. Larva up to
8 mm long; yellowish-white, subcylindrical, taper-
ing anteriorly; mouth-hooks distinctly curved and
claw-like, with the tip directed downwards (cf.
European cherry fruit fly, Rhagoletis cerasi, p.
180). Puparium 4-5 mm long, reddish-brown.
Family TEPHRITIDAE
(large fruit flies)
Ceratitis capitata (Wiedemann)
Mediterranean fruit fly
This insect is a notorious pest, capable of causing
destruction of citrus fruits, peaches and various
other fruits. Although established in many
warmer parts of the world, including areas sur-
rounding the Mediterranean, parts of Africa,
Central and South America, its occurrence in
cooler areas, such as northwestern Europe, is
usually dependent upon the initial accidental
importation of live larvae in consignments of
harvested fruits. Many countries operate rigor-
ous quarantine or eradication measures to pre-
vent this pest from becoming established. Larvae
feed within the flesh of infested fruits and cause
extensive damage; attacked fruits may drop pre-
maturely and are often invaded by secondary
bacterial and fungal pathogens. Fruits damaged
only by adult oviposition 'strikes' are also
unmarketable.
Euleia heraclei (L.)
Celery fly
The celery fly is a pest of celery and parsnip;
infestations also occur on parsley, various wild
Umbelliferae and on ornamentals such as giant
hogweed. The larvae (known as "celery leaf min-
ers') form expansive, brown, blister-like blotches
on the leaves (Plate 7a), which affect both the
appearance and vigour of host plants. Blotched
leaves curl, turn yellow and eventually become
brown; heavily infested plants appear scorched,
plant growth is checked and crop quality is re-
duced. Damage is particularly severe on young
celery plants; that on parsnip (cf. mines caused
by larvae of the moth Epermenia chaerophyllella,
p. 208) tends to be less so.
BIOLOGY
This species overwinters in the pupal stage,
adults emerging in the spring. When laying eggs,
adult females make a distinctive hole (up to
5 mm deep) in the surface of a fruit, into which
BIOLOGY
Adults appear in late April and early May. Eggs
are deposited in or on the underside of celery
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