Little Fire Ant Infestation in Waimanalo Covers Four Acres

Posted on Apr 14, 2014 in Main

April 14, 2014 

HONOLULU — An extensive survey of an area in Waimanalo has determined that approximately four acres are infested with little fire ants (LFA), tiny invasive ants that can inflict painful stings.  Crews surveyed more than 50 acres from Kumuhau St. to Mahailua St. in Waimanalo and determined that the infestation area is on state land and in mulch areas located outside nurseries in that area.  LFA was detected previously on hapuu from Hawaii Island a few nurseries and garden shops earlier this year, but those areas were treated and are now clear of LFA.

Survey operations were headed by the Hawaii Department of Agriculture (HDOA) and involved several agencies including: the Department of Land and Natural Resources, Hawaii Ant Laboratory, Oahu Invasive Species Committee, U.S. Fish & Wildlife Service, Coordinating Group on Alien Pest Species, Hawaii Invasive Species Council, The Nature Conservancy, University of Hawaii, City & County of Honolulu, and Hawaii National Guard. 

“The collaboration among agencies on invasive species emergencies has been critical,” said Scott Enright, chairperson of the Hawaii Board of Agriculture. “We appreciate the excellent assistance other agencies have provided in the field.”

Crews went out on April 3 with 16 surveyors and on April 10 with six surveyors and collected more than 1,200 samples, of which 60 were positive for LFA.  Samples were taken by placing peanut butter in a plastic vial and left out for about an hour.  The samples were collected and logged by Global Positioning Satellite (GPS) and taken back to the lab for analysis under microscope.

LFA experts are being consulted as HDOA develops a pesticide treatment plan.

“We expect that treatment of the area until the ants are eliminated,” said Neil Reimer, PhD., administrator of HDOA’s Plant Industry Division. “Once we eliminate the ants, we will have to monitor the area for three years to make sure we got them all.”

LFA has been found on Hawaii Island since 1999.  In late December 2013, LFA was detected on hapuu logs (Hawaiian fern) at retail stores on Maui and Oahu. Since its detection, Oahu and Maui nurseries have been surveyed.  Five Oahu nurseries, three of which were in Waimanalo, were found to have small infestations of LFA, which were treated and are clear of the ants.

Originally from South America, LFA is considered among the world’s worst invasive species.

LFA are tiny ants, measuring 1/16th inch long, are pale orange in color and move slowly. LFA move slowly, unlike the Tropical Fire Ant which is established in Hawaii, which move quickly and are much larger with a larger head in proportion to its body. LFA can produce painful stings and large red welts and may cause blindness in pets. They can build up very large colonies on the ground, in trees and other vegetation, and buildings and homes and completely overrun a property.

Homeowners can help the state survey their yards by placing a chopstick smeared with a little peanut butter in the yard for about one hour and put the stick in a sealable plastic bag and freeze the sample for at least 24 hours and then send it to the HDOA. Surveying instructions are available on the department’s website at:

Suspected invasive species should be reported to the state’s toll-free PEST HOTLINE – 643-PEST (7378).

For updated information on LFA in Hawaii, go to the HDOA website at:

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