An update on the management of the invasive yellow crazy ant in Australia.
With the media focusing on the red imported fire ant infestation in southeast Queensland, it’s easy to forget there is another invasive ant in Queensland causing major concern: the yellow crazy ant.
The yellow crazy ant is thought to have first arrived on Christmas Island sometime before 1934 and there is likely to have been several incursions into mainland Australia. The yellow crazy ant is now found in the Northern Territory, Queensland and northern NSW. In Queensland notable infestations exist in the Wet Tropics, Cairns, Townsville, Hervey Bay and some southeast Queensland suburbs, particularly in the Moreton Bay area.
Like many invasive ants, the yellow crazy ant has the potential to form super colonies, which can dominate the environment. Although they don’t bite or sting, they spray formic acid. When present in large numbers they decimate local wildlife – invertebrates, reptiles and birds are all affected. It is the widespread infestations in the tropics that are of most concern. Not only do they have the potential to cause untold environmental damage, in infested residential areas lifestyles are seriously affected and house prices are impacted.
Yellow crazy ant is not going to be eradicated from Australia; it is a question of management. However, targeted efforts are being made to eradicate the ant from specific areas of significant natural importance. The major focus is on eradicating the ant from the Wet Tropics. The Queensland Government announced in October 2025 that it would provide an additional $6 million as part of the ten-year funding program to support the Yellow Crazy Ant Eradication Program (YCAEP). The program is focused on eradicating the ant from the Wet Tropics World Heritage Area, to protect the natural environment and safeguard the tourism industry. It will also protect local agriculture and residential areas.
The program has had some significant wins to date, with the Wet Tropics Management Authority recently declaring that they had achieved the single largest eradication of yellow crazy ants in the world – a 390 hectare area south of Cairns, consisting of rainforest, farmland and suburban areas. The key product used in the eradication program is a specialised fipronil ant bait (used under permit), which utilises a fish meal matrix.
It is important for pest managers to be able to identify yellow crazy ants as they are a category 3 tramp ant under the Queensland Biosecurity Act 2014. This means “They must not be given away, sold, or released into the environment”, which doesn’t really make sense. However, under the general biosecurity obligation for tramp ants, a treatment should be carried out. Although it is not a requirement to report the sighting, if the ant is new to your area, it can be reported to Biosecurity Queensland. Your local council could also be contacted, as they may have a yellow crazy ant program in place.
