Effect of El Niño on Mosquito Numbers in Australia

With El Niño weather patterns taking hold in 2024, there is likely to be a significant effect on mosquito populations.

With Australia now in an El Niño weather pattern, with hotter and drier weather predicted, what does this do to the mosquito numbers around the country?

The biggest impact will be in areas inland from the coast, where the drier conditions will quickly reduce potential breeding sites, causing a drop in mosquito numbers and subsequent need for mosquito management. Bad for the pest control industry, but good for the general public, as reduced mosquito numbers in these areas will also mean fewer cases of mosquito-borne diseases such as Murray Valley and Japanese encephalitis.

However, unless the El Niño weather pattern becomes very severe, it is unlikely to have much of an impact on the coastal areas. This is because breeding sites for saltmarsh mosquitoes are tidal and less influenced by rainfall, meaning mosquitoes will continue to breed and maintain populations. For the main cities, which are also coastal, even in an El Niño weather pattern, coastal areas do still get rainfall and storms, which is generally enough to maintain mosquito numbers in cities as well (although perhaps not to plague levels). However, a prolonged dry period will certainly dry up standing water bodies and reduce the number of container-breeding mosquito species.