Little fire ants are native to South America. Over the last 100 years, thanks to the increased pace of trade, humans have been spread these tiny pests throughout the tropic; Papua New Guinea, Soloman Islands, New Caledonia, Tahiti, and recently Guam and Hawaiʻi. Genetic evidence suggests that they may have reached Hawaiʻi via Florida, potentially hitchiking in plant material shipped to Hawaiʻi Island.
Spread of little fire ants throughout the state:
1999 — In March, Pat Conant with the Hawaiʻi Department of Agriculture first identified little fire ants in a sample collected by a resident of Hawaiian Paradise Park in Puna. Surveys found several infestations in Hawaiian Paradise Park and one in Kapoho. By August, the ant had been found on a 20-acre fruit orchard in Pāpaʻikou. The little fire ants likely arrived in a windbreak planted in 1995, indicating LFA were established in some commercial nurseries at least four years earlier. In total, the ants were present on nearly 40 acres by the time they were first detected; there were no methods for applying an ant pesticide to trees, and no pesticides registered for use on fruit trees.
2009 — In October little fire ants were discovered on Maui on a single property in Waiheʻe. A multi-agency response team sprang into action the treatment strategy developed by the Hawaiʻi Ant Lab led to the eradication of the Waiheʻe population.
2010 — In early 2010, several outbreaks were found in Kona on the west coast of the Big Island. These have increased over the past 2-3 years and they are now scattered throughout the Kailua-Kona district from North Kohala down to Captain Cook. At present, the number of known infested sites is still very low, but this will probably increase.
2012 — Little Fire Ants continue to spread in the Puna District and populations are detected in Mountain View and Volcano on Hawaiʻi Island.
2013 — In December 2013, a Maui resident purchased a hāpuʻu fern at a garden shop. She tested the fern only to find LFA. Thanks to her actions and the traceback efforts of the Hawaiʻi Department of Agriculture, inspectors discovered LFA moving in hāpuʻu shipped from Hawaiʻi Island to Oʻahu, Lānaʻi, and other places on Maui. On Oʻahu, press about a related detection in Waimanalo led to residents in Mililani reporting a 20 house infestation in their community.
On Hawaiʻi Island, little fire ants are detected in Nāʻālehu in the Ka’ū District and throughout West Hawaiʻi in Captain Cook, Hōnaunau, Kainaliu, Kealakekua, Hōlualoa, and Kailua-Kona.
2014 — In September of 2014, the Maui Invasive Species Crew was surveying for the invasive miconia plant when they stumbled into an infestation of little fire ants in Nāhiku. The infestation is estimated at 35 acres. On Hawaiʻi Island little fire ants are found in Waimea and communities in the Hāmākua District including Honokaʻa and Waipiʻo Valley.
2015 — In January, LFA were discovered on Maui again when a Huelo resident reported what he thought may have been little fire ants. The infestation is approximately 4 acres. New infestations are discovered on Hawai’i Island in Hāwā in North Kohala, and Pāhala.
2018 — In December 2018, HDOA confirmed a report by Kāneʻohe resident a of stinging ants were indeed LFA. HDOA and HAL staff treated 11 properties in the Alohaki St. area on January 24th, 2019. The area will undergo the treatment plan developed by HAL researchers, several types of pesticides and bait formulas are applied on a six-week interval for a total of eight treatments. Monitoring of the area will continue for several years.
2019 — A series of reports by residents have resulted in the discovery of 7 LFA infestations on Oahu since January. One report was from a resident that had bought a plant from a school plant sale, and that plant contained a colony of LFA. One additional site on Ward Avenue was discovered by HDOA staff surveying for a different species, but finding LFA in bags of mulch along a fence. All sites are undergoing treatment by HAL and HDOA staff, sometimes assisted by OISC and other resource protection agencies and groups as cooperative projects and cross-training. All eight sites are currently believed to be within current capacity to eradicate if staffing and resources remain at existing levels. On Maui, LFA were reported from a new location after hearing media stories on LFA. October also marks the beginning of a large-scale eradication effort by HAL, MISC, and HDOA in the Nahiku area.
To date, Molokaʻi remains free of the little fire ant, and incoming plant material is surveyed regularly.