|
The maggots of the Sciarid Flies in the compost are translucent appearance
- with a slight orange or white colouring and a black head. However,
bearing in mind the small size of the grub, the head may not be
noticeable.
Peat based composts are favoured by the Sciarid Fly
Gnat - providing a plentiful supply of decaying organic matter (Peat)
for the young maggot to feed upon. Damage to fine roots is probably
incidental in the maggot's quest for food, as the fine roots will be
embedded in the peat compost.
Disease Carrier
The Sciarid Fly is also known as the Fungus Gnat,
because it has been proven to carry various fungus spores such as
Pythium, Botrytis and Fusarium. Each of these fungi diseases are harmful
to plants. Sometimes plants collapse or at least lose vigour and health,
because of the fungal disease attacking the fine roots, causing the
plant to die. In the glasshouse, small seedling can be affected, as the
Sciarid Fly lays its eggs in the compost used for seed sowing. By eating
into the fine root hairs of the young seedling, the plant wilts. Damping
Off disease is often blamed, whereas it is actually physical damage by
the maggots which is the real cause.
As well as being a pest of house plants, the flies
can be a pest where plants are grown by Hydroponics, as they are happy
to lay their eggs - and therefore maggots - in the Rockwool material
often used in Hydroponics.
The Sciarid Fly, Gnat, Midge, does not directly harm
the plants - but are a pest when flying around indoors.
Pot grown plants and greenhouse - glasshouse - plants
normally have to be watered regularly, and this provides the perfect
environment for the fly., which loves the humid conditions artificially
induced.
Treatment and Control
Sciarid flies can be controlled by a contact spray such as
Bifenthrin, but also by a soil drench. the latter is effective if the
adult flies are seen, because it almost certain that the eggs will have
been laid in the compost.
Sticky Yellow Traps are a good idea in the greenhouse
- also indoors if practicable, for they do trap a large number of the
gnats - also other flying insects that may be a trouble, such as
whitefly.
|
