Black flies are aggressive biters found in areas around streams and rivers. The black fly family is widespread in Australia, reaching a vast distance inland. The Austrosimulium pestilens, black fly species cause the most intense attacks. These species they are found in the north-eastern parts of Australia.
Black flies usually do not present in large numbers within the Logan area. The population may increase greatly following heavy rain and flooding. The flies can cause allergic reactions from bites, as well as bacterial skin infections from scratching. They are not known to transmit disease.
Adult flies commonly emerge in large numbers between 10 to 14 days after the flooding. The females viciously attack humans and animals. Once flood water recedes the number of black flies rapidly decrease. Black flies are active only during the day and do not bite at night. Their peak activity period tends to occur from sunrise to mid-morning (10:00am), and then late afternoon (4:00pm) to sunset. Female black flies are blood feeders.
Control
Black flies are widespread, especially after heavy rainfall. They are highly mobile and readily move away from breeding grounds in search of a meal. Chemical control is extremely limited. In comparison to mosquitos, treating Black Fly larvae does not work due to their habitats (running water) and life cycle.
Temporary relief from black flies can be acheived through spraying of vegetation and structures, in known areas.
The best defence against Black Fly is personal protection.
Prevention
Black fly bites can be avoided by:
- applying insect repellent
- using physical barriers, like nets on prams and cots, to protect babies under three months old
- avoid outdoor activity during the morning and afternoon when possible
- keep your shirt closely fastened (shirts with zippered fronts keep flies out better than buttoned shirts)
- tuck trousers inside socks or high boots
- ensure insect screens on doors and windows are intact
- use a knock-down insect spray in living areas.
Personal insect repellents containing DEET, or picaridin, tend to last longer than other insect repellents. This is depending on the concentration. Always use repellent in accordance with manufacturer's instructions.
To find help and advice, visit Black flies - Health and wellbeing - Queensland Government .