Oviposition normally takes place near the base of the stem. Larva
forming external stem-mine, feeding first upwards for as much as
30 cm, then turning and continuing downwards. A number of larvae
may feed in a single stem and young plants may turn yellow and die.
Pupation immediately beneath the epidermis (Spencer,
in the rind of the stem, just above the ground. A corridor from
there runs upwards for about 30 cm, then reverts and descends to
about ground level. Pupation in the mine, just below the epidermis.
Usually several mines on one plant; the plant can effectively be
ringed and be killed (Bladmineerders van Europa).
Larva: The larvae of flies are leg-less maggots without a head capsule (see examples). They never have thoracic or abdominal legs. They do not have chewing mouthparts, although they do have a characteristic cephalo-pharyngeal skeleton (see examples), usually visible internally through the body wall.
The larva is described by Dempewolf (2001:
Puparium: The puparia of flies are formed within the hardened last larval skin or puparium and as a result sheaths enclosing head appendages, wings and legs are not visible externally (see examples).
Pale or darker brown; posterior spiracles each having about 16 bulbs
(Spencer, 1976: 78).
Recently simplex has been treated as a species of Hexomyza.
It is a pest of Asparagus.
Hosts in Great Britain & Ireland:
of year - mines:
June-August (Hering, 1957).
of year - adults: Currently unknown.
in Great Britain & Ireland: Occuring wherever the host plant
is regularly cultivated. Oxfordshire (Oxford), Lancaster (Formby),
Kent (Godmersham), Surrey (Wisley), Dorset (Chickerell), Hertfordshire (Harpenden),
Worcester (Evesham) and Suffolk (Newmarket) (Spencer, 1972b: 22).
Distribution elsewhere: Europe (Spencer,
1976: 77) including Germany (Dempewolf,
2001: 79), Denmark, French mainland, Hungary, Italian mainland
and Poland (Martinez in Fauna Europaea).
recorded in the U.S.A. and eastern Canada (Spencer,
NBN Atlas links to known host species:
British and Irish Parasitoids in Britain and elsewhere: