Adult
A small robust dark fly about 4mm from tip of head to end of
wings, often seen sitting on plants, compost or substrate. The
antennae are short and stubby and each wing has five pale spots.
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Shore fly adults caught on a sticky trap, top view (left) and
side view (right).
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Egg
A small oval white egg with a patterned 'netted' surface. Eggs
are laid on the surface of damp compost and algae.
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Larva
A brown larva without a distinct head, found on the surface
of damp compost and algae, on which they feed. Often difficult
to see as they are a similar colour to the compost.
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Pupa
Similar to the larva, tapered at both ends and with a forked
'tail', made up of two breathing tubes with black tips. Pupae
do not move and are found on the surface of compost, algae or
sides of pots. The pupa shown here has its head slightly buried
in the mesh.
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Damage
Shore flies feed on algae and do not cause direct damage to
plants. The adults can be a nuisance to nursery staff and the
presence of flies or faecal droppings, seen here on a young
basil leaf, can cause marketing problems. The flies are also
potential carriers of diseases e.g. Pythium and Thielaviopsis.
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Biological
control agents
Atheta coriaria
Adult
A small black shiny 'rove' beetle, 3-4 mm long with short wings.
Very mobile, tends to burrow into the growing medium but can
also be seen under pots or flying. Feeds on various soil-dwelling
invertebrates including shore fly eggs, larvae and pupae.
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Larva
Small larvae, 1-4mm long depending on age, the small ones are
white/cream and the larger ones are light tan in colour. Has
a head capsule and three pairs of legs at the front end (top
right, only one leg visible on 3rd body segment behind head
capsule). Feeds on various soil-dwelling invertebrates including
shore fly eggs, larvae and pupae.
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Aphaereta debilitata
Adult
A very small parasitic wasp about 1.5mm long, with long 'beaded'
antennae. Occur naturally on nurseries using IPM. Can be found
on the surface of the compost or on benches or floor where shore
flies are present.
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Aphaetera on sticky traps. The male (left) has very narrow
wings. The femal (right) has paddle-shaped wings with distinctive
veining.
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Cultural control
Avoid algal growth.
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Mass trapping techniques
Horizontal traps catch more shore flies than vertical traps.
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Vertical moving trap, over plastic ' fingers' which disturb
the flies from the crop.
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Hand sweeping
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Fly suction trap over moving benches
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