PEST
 
   NAME
     Fungus Gnats, Sciarid Flies
     Various Fungus Gnat Species
 
   ORDER
     Diptera
 
   FAMILY
     Mycetophilidae

Description of the Pest
The adults are tiny gnats (flies) with long antennae and commonly occur in colonies. They fly close to, or actually run over, the ground. The legless larvae are whitish with a black head, growing up to 5mm long and have chewing mouthparts.

Life Cycle
These insects have a Holometabolous life cycle, ie. When metamorphosis is observed during the pupal stage.
The female lays up to 200 eggs that hatch in 2 to 3 days. The larva pupates in the growing media and, under optimum conditions the life cycle takes 3 to 4 weeks.

Period of Activity and Distribution of the Pest
The pest occurs in the warmer months and, when temperatures are over 24 deg. C, breeding is continuous. Its distribution is wide spread and, under glasshouse conditions, breeding can occur throughout the year. It prefers a moist sheltered position, particularly soils with a high percentage of organic material, and is associated with over-watering. 

Damage Caused
The larvae feed on fungus associated with decaying organic matter and may also feed on living tissue, such as root hairs or young roots and crowns. This can be a large problem in propagation nurseries where heating and misting are involved, as seedlings and cuttings are attacked.

Susceptible Plants
This pest is associated with growing media rather than individual plant species. Seedlings, indoor plants and containerised plants are prone to poor growth as a result of infestation in the soil.

Cultural Control
Discard infested soil and repot plants into new media. Avoid over-watering potted plants and use soil mixes with a low percentage of organic matter.

Biological Control
Parasitic nematodes are commercially available and are quite effective.

Chemical Control
The growing media can be drenched with the appropriate insecticide.
Note
Always read the label for registration details and direction of use prior to application of any chemicals.