Over the last few years, Formosan subterranean termites have increased their distribution in South Carolina.
Where Are They, And What Should I Know About Them?
There are eight species of termites in South Carolina. Four species are drywood termites. Four species are subterranean termites. Subterranean termites are the ones that do the most damage and are the focus of most termite treatments. Three of the subterranean termite species are native to the Palmetto State. However, one was introduced into South Carolina in the 1950s and is exotic: the Formosan subterranean termite, Coptotermes formosanus. Of all the termite species in SC, Formosan termites can be the most destructive and the more challenging to treat.
As social insects, termites spend most of their time hidden away with the colony, eating wood (cellulose). However, about once a year, a mature termite colony produces winged forms of termites called alates or swarmers. Swarmers are the way an established colony makes new colonies. Native termites usually have swarms in the early spring, often in the afternoon. Formosan termites often have swarms from mid-May to July, often in the evening, with the swarmers attracted to lights. An increase in mild winters and urbanization over the years in SC have probably made conditions favorable for Formosan termites to spread.
In appearance, native termite swarmers tend to be about 3/8 inch in length, black, with 4 wings of equal length longer than the body. Formosan termite swarmers tend to be about 1/2 inch in length, golden brown, also with 4 wings of equal length longer than the body.
Formosan subterranean termite swarmers (top) are about ½ inch in length and golden brown, and native subterranean termite swarmers (bottom) are about 3/8 inch in length and dark in color.
Photo credit: Dan Suiter and Brian Forschler, University of Georgia.
Formosan termites do not occur everywhere across South Carolina. Research and citizen reports documented by Clemson entomologists show Formosan termites as being established in 16 counties, Aiken, Bamberg, Beaufort, Berkeley, Charleston, Colleton, Dorchester, Georgetown, Horry, Jasper, Lexington, Orangeburg, Pickens, Richland, Sumter, and York counties. The discovery of Formosan termites does not mean they are found uniformly throughout a county; it just means locations in some areas of that county have had established infestations. Formosan termites tend to be most concentrated in coastal areas, from Charleston south to Beaufort. The Formosan infestations in both York and Pickens counties appeared to have been isolated events brought into the counties in old, infested railroad ties used for retaining walls. In both counties, the termites were treated, and with follow-up surveys, Formosans have not been found in those counties again, to date.
SC Counties where established colonies of Formosan termites have been documented as of June 2022. These include Aiken, Bamberg, Beaufort, Berkeley, Charleston, Colleton, Dorchester, Georgetown, Horry, Jasper, Lexington, Orangeburg, Pickens, Sumter, and York Counties.
Compiled by: Eric Benson, Clemson University.
Some individuals have referred to Formosan termites as super termites. They are not. If you were to see a native subterranean termite worker and a Formosan subterranean termite worker side by side, you would not be able to tell the difference between the two. If you gave each worker a block of wood, they would consume the wood at about the same rate. If you were to treat the subterranean termite worker and the Formosan subterranean worker with either a termiticide or feed them a termite bait, the products would kill both.
There are two main ways that Formosan termites can differ from our native species. Formosan termites can have much larger colonies, and they are also more apt to make aerial nests. While many of our native species may have colonies with about 100,000 workers, Formosan colonies may have a million or more. It is the sheer number of termites feeding that can make them consume wood at a faster rate. It is not because they are super-eaters. And if they establish an aerial nest or carton, they can be harder to detect and treat.
Clemson entomology researchers who studied Formosan termites in Charleston in the 1980s documented about 6% of the 50 Formosan colonies as being aerial colonies. In parts of Hawaii and South Florida, the documentation of aerial colony nests for Formosan termites is much higher. In 2022, aerial Formosan nests in South Carolina may now also be more common. For this reason, it is important for a pest management professional treating for Formosan termites to understand their biology and behavior to be able to provide termite control and protection for you. If you are going to have your home treated for Formosan subterranean termites, it would be in your best interest to have the house inspected from the foundation to the roof and not just around the first-floor level, as is done for most native termite infestations.
If you have Formosan termites swarm in or around your house, don’t panic. If you are not already under contract with a pest control company, take the time to interview one, two, or even three companies for inspection and service. If you have Formosan termites or any termites, do not feel pressure to contract for treatment quickly. While termites can damage your home, the amount of damage they will do over a few days or even a few weeks will be minimal. Take the time to make an informed decision about the company and treatment option best for you. Look for a company that offers a good written guarantee for their work. You should feel comfortable that you are hiring a pest control company that knows what they are doing.
In summary, you should be aware that Formosan subterranean termites may be in areas of Aiken, Bamberg, Beaufort, Berkeley, Charleston, Colleton, Dorchester, Georgetown, Horry, Jasper, Lexington, Orangeburg, Richland, and Sumter. They could also be expanding in other counties, especially counties adjacent to the ones just listed. If you are a homeowner, you should be concerned about them but not frightened of them. The same termite control products and strategies used to control native subterranean termites work on Formosan subterranean termites. Pest management professionals in our coastal counties have been successfully protecting homes from Formosan termite attacks for decades. The same can be done for homes in other parts of the state where Formosan termites may now be found.
For more information on termite treatments, see Termites.
For more information on how to select a pest control company, see HGIC 2412, Choosing a Professional Pest Control Company.
