In early April, a Wailuku resident met inspectors with the Hawaii Department of Agriculture (HDOA) at their office with a sample of ants he had collected from a family property on Mokuhau Street. He initially encountered the ants several months ago while cutting bamboo on the property but attributed the itching rash on the back of his neck to an allergic reaction. When he was stung near his eye, he realized there was an insect to blame. Friends suggested contacting the Hawaii Department of Agriculture. An inspector instructed him on how to collect samples of ants using peanut butter and a chopstick.
HDOA identified the specimens as little fire ants (LFA) or Wasmannia auropunctata. The next day, a team from HDOA and the Maui Invasive Species Committee (MISC) arrived in the neighborhood known as Happy Valley and surveyed 18 of the surrounding properties, including along the Wailuku River. Initial surveys indicate that LFA are present on ten properties. The infestation is estimated to be between 3 to 4 acres in size, mostly in backyards and on a heavily vegetated hillside. There were no LFA found on the riverbank.
This is the eleventh episode of little fire ants reaching the Valley Isle since 2009. MISC is actively managing five sites for LFA, with the new infestation soon to be the sixth. Treatment at the Happy Valley site has begun; however, MISC is currently unable to treat the full infestation as not all residents are allowing access. MISC and HDOA are working to resolve the issue. The source of the infestation is unknown at this time.
Area residents and anyone on Maui who suspects they may have a population of little fire ants is urged to contact the Maui Invasive Species Committee at 573-MISC (6472), the Hawaii Department of Agriculture on Maui at 873-3555, or report suspect ants online at 643PEST.org.
The little fire ant was last reported in Maui in December 2017 when the pests were found in the Kaeleku area outside of Hana and at a retail plant nursery in Kihei. LFA are no longer present at Waihee, Haiku, a South Maui resort, and a South Maui business. MISC will continue to monitor each site for at least five years to ensure that the ants are eliminated.
The little fire ant has been called one of the 100 worst invasive species globally (IUCN Invasive Species Specialist Group). They were first detected on Hawai‘i Island in 1999 and on Maui in 2009. Little fire ants reach incredible densities (80 million ants per acre) and outcompete many other insects and small vertebrates. LFA live in trees as well as on the ground. People often discover the ants by brushing against heavily-infested bushes or in windy conditions when the ants fall off plants or trees. Unsuspecting victims of the “ant rain” are left with painful stings and animals can be blinded. On Hawai‘i Island, little fire ants are now widespread. People describe being at their “wit’s end” and unable to take their keiki to the places they learned to fish, hunt, surf, and hike. Left unchecked, this species will affect Maui’s environment, agriculture, and forever change our quality of life.
Councilmember Alice Lee is sponsoring a community meeting at the Velma Santos Community Center on May 16th at 6pm. Officials from MISC and HDOA will be presenting on the threat of LFA, the current status of Maui’s infestations, the plan for treatment, and community efforts to prevent the spread. Learn more about LFA, including how to collect samples, atwww.stoptheant.org