Little Fire Ants Confirmed in 2nd O‘ahu Neighborhood

Little fire ants (LFA) have been confirmed in a second Windward O‘ahu neighborhood. A resident in Ahuimanu reported stinging ants and surveys of the area and a nearby home of a relative detected two infestation sites around Ahuimanu Road.

The main site involves 13 properties and the other site involves five properties, totaling about three acres, including 15-meter buffer zones around each site. The area was treated today by the Hawai‘i Department of Agriculture (HDOA) and the Hawai‘i Ant Lab (HAL). Crews also conducted the second treatment of the Kaneohe neighborhood where LFA was detected in December. HDOA Plant Pest Control specialists from Hawai‘i Island were also brought in to help conduct the treatments.

In late January, an Ahuimanu resident reported stinging ants and HDOA entomologists confirmed that they were LFA. Crews conducted multiple surveys of the neighborhood to determine the boundaries of the two infestations. The infestations in Kaneohe and Ahuimanu do not appear to be related.

Last week, LFA was also confirmed on a plant that was purchased at the Punahou Carnival in early February. Those who purchased plants at the carnival are also being urged to test their plants for LFA. So far, no LFA have been reported on any other plants sold at the carnival. Suspected LFA should be reported to HDOA’s Plant Pest Control Branch at (808) 973-9538.

“These recent detections should be a warning to homeowners on all uninfested islands to check for little fire ants periodically,” said Phyllis Shimabukuro-Geiser, acting chairperson of the Hawai‘i Board of Agriculture. “People traveling from infested areas should also be very cautious of potentially transporting these tiny ants in plant material, baggage and cargo.”

The Kaneohe infestation zone includes a total of 11 properties covering about two acres around Alokahi Street. That area was treated Thurday, March 7, 2019, for the second time following a treatment plan developed by HAL researchers. It involves the use of several types of pesticides and bait formulas applied in six-week intervals for a total of at least eight treatments. Monitoring of the treated areas will continue for several years.

In 2015, LFA was successfully eradicated in a six-acre infestation site in Mililani Mauka using the same treatment protocol being used in the two Windward Oah‘u infestation sites.

LFA has been found on Hawai‘i Island since 1999 and the population is widespread on that island. Since that initial detection, HAL and HDOA have developed a treatment strategy that has helped to prevent the spread of LFA to other islands.

HDOA and partner agencies, including the Invasive Species Committees on O‘ahu, Kaua‘i, and Maui County and the Coordinating Group on Alien Pest Species (CGAPS) have been asking residents on O‘ahu, Kauaæi and Maui County to survey their properties for LFA by using a little peanut butter on a chopstick and leave them in several areas for about one hour. Any ants collected should be put in a sealable plastic bag, placed in the freezer for at least 24 hours and dropped off or mailed to any HDOA office. An informational flyer may be downloaded online.

In addition, the Department of Land and Natural (DLNR) Resources has produced a three-minute video, “How to Test for LFA,” which shows the step-by-step procedure for testing for LFA.

How to test for Little Fire Ant from Hawai‘i DLNR on Vimeo.

Originally from Central and South America, LFA is considered among the world’s worst invasive species. LFA are tiny ants, measuring 1/16^th inch long, are pale orange in color. LFA move slowly, unlike the tropical fire ant, which is established in Hawai‘i, 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.

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