Through DNA studies, we can see that the LFA we have now in Hawaii are most closely related to invasive colonies in Florida. It is thought that they were accidentally introduced to Hawaii Island on shipments of plants to nurseries in Puna sometime in the 1990s.
By 2002, surveys showed that positive detections of LFA from Kalapana to Laupahoehoe, indicating they had spread far beyond the point of eradication. LFA are notoriously difficult to treat because they utilize trees to travel, and it was very difficult to get pesticides into the trees to where ants will come into contact with them.
The state Department of Agriculture is now charged with preventing the spread of LFA to other islands, and they perform inspections of goods being shipped inter-island. The HDOA’s Hawaii Ant Lab (HAL) researches methods for control of LFA and pursues new products and treatments for use in our unique Hawaiian landscape. On outer islands, staff from HDOA, HAL, and the local ISC will work together to eradicate newly discovered populations of LFA, so all homeowners on other islands should be surveying regularly and detections should be reported immediately. On the Big Island, HAL and BIISC offer training programs to residents for LFA treatment.
Other species of ants already wreak havoc on our native bird populations. In the Galapagos Islands, LFA attack, blind, and kill endangered baby tortoises. If LFA were to spread into the habitats of our threatened and endangered native Hawaiian birds, it could be devastating for the animals we’ve worked so hard to protect. Even our pets are not safe: LFA will attack the eyes of cats and dogs, resulting in the formation of cataracts that lead to blindness.
LFA have a burning fiery sting that leaves itchy, painful welts that can last for weeks. They form nests wherever there is shade and adequate moisture, especially in trees. But because they can’t grip very well, they tend to fall from trees and rain down on unsuspecting people and animals, resulting in dozens or sometimes hundreds of stings. This can make picking fruit and doing yard work a painful experience. Unlike other ants, LFA will work with neighboring LFA colonies to form massive super colonies. These super colonies can force out other ants and insect species. Without treatment, LFA rapidly expand in population: densities in Hawaii can reach 20,000 ants per square meter. At this level, LFA will completely take over yards and homes.
LFA are not “builder” ants. They will not form mounds or dig complicated tunnels. They much prefer to move into ready-made spaces that provide a bit of shade and moisture, such as rock walls or within the fronds of palm trees, under the moss on the bark of a tree or under some discarded planters in the backyard. They are readily adaptable to a variety of tiny habitats.
You should also try to prevent accidental introductions. LFA don’t travel very far on their own: they are normally first introduced to a new location when people bring them in with things, like in potted plants or building materials. They can also fall from overhanging trees or get washed into your property with the rain. LFA perform something called rafting, where they group together and float when submerged in water.
On their own they spread slowly, but people and nature can speed up their spread immensely. Once the colony’s population reaches a certain point, a queen will move a few feet to yards away with a few workers and start a new colony. This is called budding, and the new colony will still stay connected with the original one. As each new colony makes new queens, the population will grow exponentially.
This is why it may seem as if the populations “suddenly” exploded. The best way to prevent a population explosion is to survey regularly, and catch any new colonies before they can expand.Establishing a quarantine area using a barrier treatment before bringing in new items is essential. Cut back foliage overhanging your property, and always survey a couple weeks after heavy rains.
To keep LFA from wandering in from adjacent properties that are infested, treat your border with a barrier spray or granular. Also make sure to survey every few months to check if the LFA are managing to move in. Be sure you are using the products correctly!
It has been suggested that it is not the ant sting that is the cause, but a bacterial infection that takes place following the puncture of the lens. There is no conclusive evidence about what impacts, if any, the LFA have on pets at this time.
We recommend that you take precautions to keep your pet food away from ants. Use a dish of water around your pet’s food bowl with a bit of dish soap in it to prevent ants from getting in to the bowl. Remove pet food bowls as soon as your pet has finished eating (don’t leave food sitting in the bowl all day). LFA are seeking protein, and pet food will be highly attractive to them!
Control of LFA
Landscaping is another way to help reduce the amount of LFA on your property. Removing excess debris, dead plant matter, and moss on trees will help to reduce the number of ideal nesting sites. Wherever possible, trim back vegetation so that it does not make contact with your house. Contact barriers around foundations and entryways can prevent ants from entering your home while you wait for baits to work in your yard.
For more information on pesticides and baits check out our Product page.
Its okay to use contact pesticides like raid in your bathroom, kitchen, and where ever the ants make living miserable. Just make sure that using Raid isn’t the only type of control that you are relying on.
Some of these products do impact fish and aquatic invertebrates, and so should not be used in or around water systems. Always read the label to make sure that baits are being used safely and properly! Find more product information on our products page.
There are also toxicant products which kill both workers and queens. Altrevin (metaflumizone) is labeled for use in citrus and mac nut and some other fruit trees. Amdro Pro may be used in trees if in a bait station. Read the label to make sure the bait is being applied to the proper area in the correct way.
If you are using a recommended product but not seeing results, the answer could lie in several areas. If the pesticide you’re using is an IGR (Tango) then it will take a few months before you will notice a population drop as the workers must live out their natural life cycle Tango affects the queen’s reproductive system. This kind of pesticide will not kill workers, but will prevent new workers from hatching. Granular products, such as Siesta and Amdro, have a short “shelf life”. Once the bag is opened and sits for some months or even weeks, moisture seeps in and the bait will become unattractive to the ants. Similarly, if the ground is wet or if it rained shortly after the granules were spread, then the bait will no longer be attractive and the water will degrade the active ingredient in the pesticide, making it useless.
If you are using a recommended product but not seeing results, the answer could lie in several areas. If the pesticide you’re using is an IGR (Tango) then it will take a few months before you will notice a population drop as the workers must live out their natural life cycle Tango affects the queen’s reproductive system. This kind of pesticide will not kill workers, but will prevent new workers from hatching.
Granular products, such as Siesta and Amdro, have a short “shelf life”. Once the bag is opened and sits for some months or even weeks, moisture seeps in and the bait will become unattractive to the ants. Similarly, if the ground is wet or if it rained shortly after the granules were spread, then the bait will no longer be attractive and the water will degrade the active ingredient in the pesticide, making it useless.
When using a toxicant there should be a drop in the worker population within a few days after application. The workers that are alive can have trouble functioning depending on what kind of toxicant was used. Some pesticides affect the nervous system, these ants would be very twitchy when moving or become paralyzed and can’t move at all. Other toxicants affect energy production making workers very sluggish.
To get rid of the colony, you must also broadcast some kind of bait in your yard. If you are still noticing a lot of ants inside after about a week, then they may have begun to nest inside. If this is the case, you want to start using bait stations inside the home. A bait station is any container that can hold pesticide. You can purchase ready-to-use products like Raid III or Raid Double Control, or use small plastic containers fill them with toxicant baits like Amdro and Siesta. You can buy refillable bait stations or use portion cups with small holes in them for the ants to move in and out of.
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