Red imported fire ant management case studies

Yarwun, Australia : Brisbane, Australia : Shihmen Reservoir, Taiwan : Whirinaki, New Zealand

Location: Yarwun, Queensland, Australia

Justification: Containment, social

Goal: Eradication

Size: 71 ha (treated an area of 1028 ha). At least 11 colonies were present.

Products: 25-40 L of liquid fipronil (2.5 ml/100 L) was injected once directly into fire ant mounds, 20 m around each mound was also sprayed.

Amdro (hyrdramethylnon 5 g/kg; corn grit and soybean oil matrix; 2.5 kg/ha) was then scattered around the immediate area in areas of high infestation.

Distance (within 8 m of water; pyriproxifen 5 g/kg; 1.6-2 kg/ha) and Engage (up to edge of water; S-methoprene 5 g/kg; 1.6-2 kg/ha) were applied using aerial and hand baiting with manual spreaders to blanket cover the infestation seven times over 18 months.

A more than 1 km buffer zone around the area of known infestation was also treated with pyriproxifen or S-methoprene (depending on how close to water the area was).

Time of year: Most of the treatments were done between September and May, as this is when the ants are most active and thus pick up more bait.

Outcome: Successfully eradicated

 

When discovered, red imported fire ant nests are directly injected with Termidor® (© The State of Queensland, Department of Agriculture and Fisheries, 2016)

Programme cost: 3.8 million AUD

Manager: Sarah Corcoran / Anthony Wright (sarah.corcorane@daf.qld.gov.au), Biosecurity Queensland

Information sources

Wylie, Jennings, McNaught, Oakey, Harris. 2016. Eradication of two incursions of the red imported fire ant in Queensland, Australia. Ecological Management and Restoration 17(1): 22-32

Further information was provided by Ben Hoffmann, Principal Research Scientist, CSIRO Land & Water Flagship, Ben.Hoffmann@csiro.au

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Location: Brisbane, Queensland, Australia

Justification: Containment, social

Goal: Eradication

Size: ~ 36 000 ha

Products: Distance (pyriproxifen 5 g/kg; 1.6-2 kg/ha); Engage (S-methoprene 5 g/kg; 1.6-2 kg/ha); Termidor (fipronil 2.5 ml/100 L)

Time of year: September to May

Outcome: Ongoing, treatment is effective (99.5% of sites lack fire ants after the third treatment)

Programme cost: AU $320 million from 2001 to present

Manager: Sarah Corcoran/Anthony Wright (sarah.corcorane@daf.qld.gov.au), Biosecurity Queensland

Sniffer dogs can detect nests that are invisible to humans (© The State of Queensland, Department of Agriculture and Fisheries, 2016)
 

Biosecurity Queensland explains their red imported fire ant treatment programme, YouTube video (© Biosecurity Queensland)

Red imported fire ants were first detected in Brisbane in 2001, the first treatment was applied within a month.

To prevent spread, infested suburbs are quarantined and residents and businesses need approval to move soil or goods out of the quarantine zone. Strict fines are in place for those who break this law.

Distance (applied within 8 m of water) and Engage (applied from 8 m up to edge of water) are applied using aerial and hand baiting with manual spreaders to blanket cover the infestation 3 times per season (between September to May because this is when the ants are most active and thus pick up more bait) over two consecutive years. A 500 m buffer zone around the area of known infestation is also treated (a buffer zone of 50 m is treated for single nest infestations).

Pyriproxyfen is preferred to S-methoprene because it is more stable and is more effective at reducing ant numbers. Mounds that cause human safety concerns are directly injected with 25-40 L of liquid Termidor, 20 m around each mound are also sprayed.

This programme has been using new technologies such as remote sensing (uses aerial imagery to detect fire ant mounds and is cheaper, faster and more effective than using surveillance teams on the ground) and sniffer dogs (dogs trained to locate RIFA by smell) to detect new infestations and remnant nests with great success.

Despite high successes with treatments (75% of sites have no ants detected after a single treatment and 99.5% of sites have no ants detected after 3 treatments), this programme has been unable to contain RIFA spread due to difficulty locating new infestations before they are well established.

This programme has also been very underfunded which has prevented an adequate level of treatment to achieve eradication. This being said, when RIFA were first detected in 2001, it was estimated that they infested 61 000 ha, as of 2013, through the efforts of this treatment programme, they now occupy approximately 784 ha.

Information sources

Lach, Barker. 2013. Assessing the effectiveness of tramp ant projects to reduce impacts on biodiversity. A report prepared for the Australian Government Department of Sustainability, Environment, Water, Population, and Communities

Wylie, Jennings, McNaught, Oakey, Harris. 2016. Eradication of two incursions of the red imported fire ant in Queensland, Australia. Ecological Management and Restoration 17(1): 22-32

Further information was provided by Christine Horlock, A/Manager Programme Support, Biosecurity Queensland Control Centre, DAF, christine.horlock@daf.qld.gov.au 

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Location: Shihmen Reservoir, Taiwan

Justification: Investigating treatment options

Goal: Eradication

Size: 13 ha

Products: Esteem (pyriproxyfen 5 g/kg; corn grit carrier; 2 kg/ha) (was applied using fertilizer spreaders 4 times over one year)

Time of year: Once per season (Nov, Feb, May, Aug)

Outcome: 98.2% reduction in worker numbers after two treatments, 100% after 4 treatments. Eradication was successfully achieved.

Programme cost: not available

Manager: Ji-Sen Hwang, National Taiwan University

Information source

Hwang. 2009. Eradication of Solenopsis invicta by pyriproxyfen at the Shihmen Reservoir in Northern Taiwan. Insect Sciences 16: 493-501

Location: Whirinaki, New Zealand

Justification: Containment, social

Goal: Eradication

Size: 1 nest (2 m2)

Products: Distance (pyriproxyfen 5 g/kg; soybean oil/corn grit carrier; 2 kg/ha); Engage (S-methoprene 5 g/kg; soybean oil/corn grit carrier; 2 kg/ha); Maxforce Pro (hydramethylnon 10 g/kg; ground silkworm pupae carrier; 2 kg/ha)

Time of year: late spring or early autumn

Outcome: Eradication was successfully achieved.

Programme cost: not available

Manager: Tim Ryder (Tim.Ryder@mpi.govt.nz), MPI

A single nest of approximately 30 000 red imported fire ants covering 2 m2 was reported to the Ministry for Primary Industries (MPI) in 2006. MPI's response was immediate and the nest was destroyed. A controlled or quarantined area was put in place within a 2 km radius of the nest site. This restricted the movement of high risk goods by those that lived and worked within this zone to prevent further spread of the ant.

This area was also intensively monitored for 3 years using pitfall traps (with and without attractive lures) and visual surveillance. Those areas that were not able to be accessed by foot for surveillance were treated aerially by helicopter. The baits Distance, Engage or Maxforce Pro were applied at a rate of 2 kg/ha. Six rounds of bait were applied to these areas over a three year period in late spring or early autumn.

After 3 years when no additional red imported fire ant nests had been found, the ant was declared successfully eradicated from the area.

Information source

Information was provided by Tim Ryder, Senior Advisor, Plants and Environment Response Investigation, NZ MPI, Tim.Ryder@mpi.govt.nz