Little Fire Ants and You- What Can You Do?
Posted on Jul. 1, 2025 / Invasive Species / Subscribe 0
By: Allison Miles
What is the primary responsibility of a landscaper? Are we simply here to keep the grass trimmed, the hedges neat, and the irrigation and lighting systems in working order? Is our job just to get in and out efficiently—or does our role reach deeper, into the health of the land, the longevity of plant life, and the stewardship of our shared environment?
While the bottom line may depend on working quickly—and client expectations often emphasize lush greenery and curb appeal—a forward-thinking landscaper understands that true success lies in creating landscapes that endure: vibrant, functional, and resilient ecosystems that invite enjoyment and well-being, free from persistent distractions caused by pests or plant health issues. It is the landscaper’s kuleana—responsibility and privilege—to diagnose and correct problems as they arise, whether related to irrigation, fertilization, soil health, or pest management.
Ants are a persistent problem in Hawaii’s landscapes. All ants in the state are introduced species—some are minor nuisances, while others are invasive threats to ecosystems, agriculture, and even human health.
In the landscape, ants don’t feed on plants directly. Instead, they form mutualistic relationships with sap-feeding pests such as aphids, scales, whiteflies, and mealybugs. These pests excrete honeydew—a sugary substance that ants consume. In return, ants protect the pests from natural predators, allowing their populations to grow unchecked.
Figure 1. Little Fire Ant tending scale. Photo credit: Melody Euaparadorn, Hawaii Ant Lab.
Figure 2. Little Fire Ant feeding on Honeydew excretions mealybug on banana leaf. Photo credit: Melody Euaparadorn, Hawaii Ant Lab.
The result is a cascade of damage. Sticky leaves, blackened foliage, and general plant decline are clear signs it's time to inspect the canopy for sap-feeding pests and follow ant trails along stems, trunks, and into the root zone. Sooty mold and plant stress are common and highly visible outcomes of heavy ant infestations, which can affect leaves, flowers, fruits, and even roots. In edible landscapes, the impact is even more pronounced—yield drops, and fruit quality suffers.
Figure 3. Scale and Sooty Mold on Alahee (Psydrax odorata). Photo credit: Melody Euaparadorn, Hawaii Ant Lab.
Now imagine all of these landscape issues compounded by a single invasive ant species—one with the power to threaten jobsite safety as well as the health and well-being of homeowners, their children, pets, and livestock.
Figure 4. Tiny Little Fire Ant on Hau (Hibiscus tiliaceus) flower bud. Photo credit: Melody Euaparadorn, Hawaii Ant Lab.
The Little Fire Ant (Wasmannia auropunctata), commonly known as LFA, is an invasive pest that some of our islands have unfortunately come to know all too well. A simple brush against a soft palm frond, reaching to pick fruit, pulling on a vine, or even sitting beneath a tree on a breezy day can result in numerous painful stings—often around the neck—that can send some people to the hospital and drive many others indoors. LFA find their way inside shirts or pants, become trapped, and begin stinging. The burning pain can ruin your day, and for some, the discomfort can linger for weeks.
Figure 5. Little Fire Ants often sting on neck after falling from plants. Photo credit: Melody Euaparadorn, Hawaii Ant Lab.
The Little Fire Ant (LFA) ranks among the 100 worst invasive species worldwide and was introduced to Hawaii through agricultural imports in the mid-1990s. It is now firmly established across much of the Big Island, with infestations recorded at elevations up to 4,000 feet. In areas of high density, LFA invade homes—nesting in drains, walls, and furniture. People are stung in their beds and baths, pets suffer eye injuries, children get stung while playing outdoors, and what should be enjoyable yardwork and recreation quickly becomes unbearable.
As LFA spreads through residential neighborhoods and agricultural lands, finding workers who are willing to work in untreated orchards becomes increasingly difficult. Ultimately, landowners face limited choices: treat the infestation, resign themselves to being stung, or alter their lifestyle. However, without firsthand experience, these warnings are often dismissed as “scare tactics.”
LFA working groups—including the Hawaii Ant Lab, Oahu Invasive Species Committee (OISC), Hawaii Department of Agriculture (HDOA), and various community action groups—are actively tracking and treating infestations. But long-term success depends on stopping the spread.
The spread of LFA is largely due to people moving infested materials both within and between islands. Hawaii Island, Maui, Oahu, and Kauai are all in different stages of invasion. Over the past two years, known infestations on Oahu have grown exponentially, and Kauai may be entering a similar phase. In contrast, Maui has taken a zero-tolerance approach, dedicating significant resources to eradicate known infestations. Their continued vigilance in monitoring for accidental introductions gives them a good chance of remaining LFA-free—while also providing a buffer against reinfestation.
Management Strategies- Disrupt the Ant–Pest Relationship
Figure 6. LFA tending scale in their mutualistic relationship. Photo credit: Melody Euaparadorn, Hawaii Ant Lab.
Landscape professionals have the power to break the pest cycle, restore plant health, and help prevent the spread of LFA. Start by maintaining healthy soil and avoiding excessive nitrogen fertilization, which can contribute to outbreaks of sap-feeding pests. By managing these pests effectively, you eliminate one of LFA’s primary food sources and reduce their presence in the landscape.
Designing landscapes with LFA prevention in mind can reduce the likelihood of infestations taking hold. Select plant species that limit LFA habitat and allow for more effective pesticide application. Design planting layouts with enough space to walk between plants for monitoring and treatment, and maintain vegetation at a height that is accessible without special equipment. Thoughtful design can significantly hinder LFA establishment and reduce long-term management challenges.
Prevention
Although it is not the only pathway, the movement of landscape materials and outplanting of infested nursery stock is likely the greatest cause of LFA spread. Fortunately, it is also one of the easiest to mitigate through reasonable precautions. Whether we grow our own planting stock or purchase materials from large nursery retailers, we are also in a unique position to support early detection and support prompt treatment.
The first step is to maintain control over the biosecurity of your jobsites and do everything possible to prevent the spread of LFA. Prevention begins with sanitation—both phytosanitation and equipment decontamination. LFA can live on virtually any surface, including mulch, wall crevices, potted plants, lawns, under pavers, and in trees. Removing vines, pruning trees, and keeping hardscape and storage areas clean helps reduce nesting habitat.
Figure 7. A LFA colony in weedmat can host multiple queens and thousands of workers. Photo credit: Hawaii Ant Lab.
As a precaution, decontaminate equipment by washing off mud and debris at a designated location between jobs. Sanitation not only reduces the risk of transporting LFA between sites, but it also improves the effectiveness of treatments by minimizing habitat availability. Screen your vendors carefully; ask about their pest control and LFA treatment policies. If they cannot provide adequate answers, consider sourcing materials elsewhere.
Set up a staging area—free of weeds and insects—Test all incoming plant and landscape materials before accepting them, and inspect equipment for LFA before unloading. Monitor for LFA using peanut butter lures to detect their presence. Subcontractors and employees should be required to follow Best Management Practices (BMPs) and arrive at the jobsite with clean vehicles and sanitized tools.
Figure 8. Bamboo stick with a thin layer of peanut butter quickly attracts Little Fire Ants for monitoring. Photo credit: Melody Euaparadorn, Hawaii Ant Lab.
Monitor and Identify: No prevention program is foolproof—accidents can still happen. Older landscapes should be tested for LFA at least at least once a year, and newer installations should be tested at least every six months for early detection. To test for LFA, use a chopstick baited with peanut butter—or mayonnaise for those with peanut allergies. Any ants that are collected can be sent to Hawaii Ant Lab for free identification and treatment advice—you can then implement a targeted treatment approach. Make sure to regularly inspect your growing area and test your stock before transport.
Control Ant Populations: Ant control is very different from other types of pest control. With limited exceptions, landscapers are not legally able to provide add-on LFA control services without holding a valid pest control license and being properly insured for pest control under Hawaii law (Hawaii Administrative Rules Ch. 94). These regulations are governed by the DCCA Pest Control Board.
If you choose not to obtain a pest control license, partner with someone who is qualified and trained in LFA management. As a landscape professional, you can also play a key role in educating your clients about the importance of proper pest identification and Integrated Pest Management (IPM). When clients understand the basics of IPM, they’re better equipped to evaluate potential pest control providers—and to ensure that effective LFA treatment is part of the contract before work begins.
Hawaii Ant Lab: For more information on Little Fire Ants, inquiries, and to register for a free zoom class, visit littlefireants.com. Hawaii Ant Lab staff are available for free consultation and trainings. You can refer clients or provide them with information on self-treating their yard. To order a test kit and send in your samples for a positive ID, visit stoptheant.org. Hawaii Ant Lab also has a vast selection of user-friendly info sheets and comprehensive “how-to guides” for LFA prevention and control that you are welcome to use for education and prevention strategies.
Allison Miles is an Outreach Technician at the Hawaiʻi Ant Lab (HAL) on the Big Island
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