ABC PEST CONTROL

Description: The fungus gnats are flies about 4mm in length and are small, black with a very distinctive pointed abdomen.

Biology: The Gnats are often found in offices and domestic environments; usually associated with stagnant water in plant pots and displays. Occassionally they can be associated with bath and sink overflows and stagnant water that may have resulted from leaks. Sometimes the Gnats breed in condensation drip trays used in air conditioning systems. The females are parthonogenic (not needing males to breed). Larva can be supported by material in plant pots especially if a plant or bulb has died and is decomposing. The pupa hatch in this medium.

Control: This is often difficult to achieve, generally you should isolate plants likely to support the flies and ensure that they are in good order before being re-introduced. An horticulturist can carry out a treatment in the void below the plant. Sometimes extreme action has to be taken because of complaints, in these cases the area affected is treated with a fog or mist using ULV (Ultra Low Volume) insecticidial material. Residual spray treatment is not often effective and tends to make office inhabitants relieved rather than having any toxic effect on the insects.