In Australia there are around 400 species of mosquito but only approximately 10 are commonly abundant and represent a serious pest threat because of their nuisance biting or their ability to transmit disease. Mosquitoes lay their eggs in stagnant water source such as wetlands, both natural and constructed, rain water tanks, pot plant saucers, plants that hold pools of water, hollows in trees, gutters and other items that may be left around that retain water.
The eggs can hatch within a few days and the larval stage begins. Mosquito larvae are aquatic and must live in a water source to survive and complete their development stage. Once the adult female emerges it will seek out a carbohydrate meal to replenish its energy. The female mosquito will mate with a male generally not far from the breeding site. For development of the eggs the female will need a high protein meal and this may be obtained from a source such as blood.
Batches of eggs can vary from 20 to 30 to several hundred depending on the species. Many mosquito species typically move only relatively small distances (sometimes no more than 50-100 metres) from their larval habitats provided appropriate blood sources are in the vicinity. However there is one species able to disperse up to 50 kilometers.
Several important human diseases are transmitted throughout Australia by these insects including Dengue fever, Australian encephalitis, Ross River virus disease and Barmah Forrest virus disease. Malaria has been transmitted locally in Australia but only rarely in recent decades.
In addition to being disease vectors, mosquitoes can cause major disruptions to occupational, recreational and social activities through their persistent biting.
Successful management of this pest depends on a variety of factors including familiarity with mosquito biology and identification. Identification of breeding sites is important to be able to treat mosquitoes in their larval stages in conjunction with an adult mosquito management plan that may involve treating harbourages such as vegetation and exterior walls of a property with a repellent product.
Simple measures can be taken by individuals to limit their contact with mosquitoes. Areas that are known to be infested with large numbers of mosquitoes should be avoided. Activities that are scheduled for outdoors, especially around dusk, should be limited as the biting activity of many mosquitoes will peak during this period. Clothing that has long sleeves and long pants should be worn when visiting areas that are infested with mosquitoes. A repellent that contains approx. 20% DEET (diethyl toluamide) should be used on exposed areas of skin but not repeatedly on young children. Windows and doors should be screened and water tanks covered with a small gauge mesh to exclude mosquitoes from these potential breeding sites. Empty all containers throughout the garden that hold water such as pot plant saucers, tyres, roof guttering and tins to prevent breeding.