Department of Agriculture

HONOLULU — A four-month effort by the Hawai`i Department of Agriculture (HDOA) to eradicate a type of stinging ant on Maui is proving to be highly successful.   Little fire ants (LFA) were reported on a farm in Waihee in October 2009, with an area of infestation covering about a half acre.  HDOA initiated a rapid response plan to contain and eradicate the ants and after four treatments, no ants have been found at the site. Treatments will continue for at least eight more months to help ensure that LFA has been eradicated.  To date, LFA has not been detected anywhere else on Maui.

Since the LFA was discovered at the Waihee site, HDOA personnel from Maui, O`ahu and Hawai`i Island have been working to treat the area and prevent the infestation from spreading to other areas.  A key component of the treatment plan has been a special experimental ant bait developed by HDOA scientist Cas Vanderwoude to control ants in trees.  HDOA obtained a special experimental permit from the Environmental Protection Agency to test this method.

“The experimental bait has been very effective,” said Neil Reimer, Ph.D., manager of HDOA’s Plant Pest Control Branch. “Until now, there were ground treatments but no effective treatment method to control little fire ants nesting in trees. There is no chance of eradication without a treatment on trees.

“We also appreciate the continuing cooperation of the property owner during our eradication effort,” Reimer added. “Their assistance made our job easier and contributed greatly to the success in eliminating this serious infestation.”

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.  They can produce painful stings and large red welts and may cause blindness in pets.  They can build up very large colonies on the ground and in trees and other vegetation and completely overrun a property.  They will also freely move into homes.

The first detection of LFA in Hawai`i was in the Puna area in 1999.  Surveys determined that LFA appeared to have been on the west side for several years prior to their initial detection and was widely distributed in Puna. Attention was then focused on controlling ant populations and preventing the spread to uninfested areas on the island and to other islands; however, containment on Hawai`i Island has progressed beyond the capacity of HDOA.  In January 2010, LFA was found at two locations in Kona and it is believe more infestation sites are likely.

“The apparent success of the effort on Maui demonstrates how we have a better chance at eradicating invasive pests if they are recognized and reported before they become widely established,” said Sandra Lee Kunimoto, Chairperson of the Hawai`i Board of Agriculture. “We need everyone to be looking out for unusual or new pests and to report it.”

HDOA, Maui County, the Maui Invasive Species Committee and the U.S. Geological Survey are working together to survey areas on Maui and to develop public awareness programs.  Suspected LFA or other stinging ants should be reported to:

HDOA Maui Office – 873-3962

HDOA Hawai`i Island Office – 974-4140

Or to the State’s toll-free PEST HOTLINE at 643-PEST (7378).

Attached is an HDOA Pest Advisory that contains information on LFA and its history in Hawai`i.
The advisory is also available on the department’s website at:  https://hawaii.gov/hdoa/pi/ppc/npa-1/npa99-02-lfireant.pdf

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