Fire ants spread slowly on their own – so how are they getting to so many areas on the Big Island? Little fire ants like to hide in small nooks and crannies so it is very easy for them to hitch a ride in our stuff. LFA have been known to spread in potted plants, gravel, mulch, and construction material. Anything that has been sitting for a while has the potential to host LFA. But there is a way to continue to bring things onto our property without the fear of spreading LFA:
Anything that is brought onto your property should be kept first in a specially prepared area and monitored, to reduce the chance of brining LFA onto your property. This is especially important if you have not yet found the ants on your property, or have been able to successfully control LFA and bring your numbers down to zero.
What should be quarantined? All live plant materials should be quarantined of course, but also anything that may have been sitting outdoors for awhile in a potentially infested area. Be cautious with all materials – when in doubt, keep it out.
Large items (generally those that may have sat for 2 weeks or more in a potentially infested area – particularly anywhere in Hilo or Puna – including parking lots, backyards, garages, store lots). Examples of where we’ve seen LFA include cars, building supplies (piles of wood, tiles, roofing), equipment (mowers, weed whackers, etc. if they have not been used recently), used furniture, and yes, Christmas trees!
To quarantine these items, use barrier pesticides (ex. Talstar, Upstar, Bifen, Ortho Max HomeDefense) in a flat clear area to create a quarantine zone. Apply pesticide as directed by the label. Barrier pesticides will create a space the ants won’t be able to cross. Place the item(s) within the quarantine area and let it sit undisturbed overnight, so the ants will get comfortable enough to emerge from their hiding spots. Place a chopstick with peanut butter within the quarantine zone and wait 30 minutes to an hour. If there are no ants, you can remove the object from the quarantine zone and use it with confidence! If ants are found, don’t despair. You can treat the object (or return it to its previous owner!).
To treat, leave the item(s) in the quarantine zone, and sprinkle lightly with a toxicant granular bait such as Amdro, Siesta, or Max Force Complete. Because of the quarantine zone, the ants won’t be able to forage elsewhere, and will be forced to feed on the baits. After a few days, check again with peanut butter to see if there are sill any ants that are still alive. If ants are found, reapply toxicant baits. Do this every few days until LFA are gone.
Landscaping materials – piles of mulch, cinder, macnut shells, etc.
If you are ordering materials from a supplier, always ask their protocols and policies around little fire ant before accepting a delivery. They should be able to tell you clearly exactly how they control and prevent LFA – if not, you may want to look for a different supplier!
If possible, deposit the materials in a pile in a prepared quarantine zone, as described above, and test with peanut butter sticks. If ants are found, you can use a similar method as described, force-feeding the ants a granular bait product. You can then spread the product where you need it after no ants are found. If the materials are brought in and spread over a wide area and cannot be deposited in a pile, then you will want to be vigilant about using peanut butter sticks to monitor every area where the new materials are laid. Keep in mind that if you do find LFA in this situation, treatment may be more difficult and costly than a quarantine zone treatment.
On mulch, Hawaii County has been working with their contractor and the Hawaii Ant Lab to control little fire ants at mulching locations, to great success. However, better safe than sorry – it is best to use a quarantine zone if at all possible before bringing anything on to your property.
Small items: Potted plants, cut flowers
You can use the same method as large objects, or you can make a simple moat. Fill a container with a little bit of of soapy water. The soap will break the surface tension and cause the ants to sink instead of floating on the surface. Place a smaller container upside down in the water to create and ‘island’ and place the potted plant on top. Give a few hours for the ants to settle then check for LFA with peanut butter. If ants are found, treat the object or return it. To treat something in the quarantine zone remove the chopstick with peanut butter and use a toxicant granular bait such as Amdro, Siesta, or Max Force Complete. Sprinkle the granular inside the pot (make sure the soil is dry). Because of the moat, the ants won’t be able to forage and will be forced to feed on the baits. After a few days, check again with peanut butter to see if there are still any ants that are still alive. If ants are found, reapply toxicant baits. Do this every few days until ants are gone.
Need more info on barrier treatments? Check out our LFA Control Products page!
Hilo and Waikaloa free county mulch is being monitored by the Hawaii Ant Lab for LFA and other pests. Check out their page here for more info.