Around 50 termite species have been documented in the United States, but few of these species are categorized as pests to structures. Unsurprisingly, the most widely distributed termite species in the US is also the most destructive. This species is commonly known as the “eastern subterranean termite,” and it can be found in all states east of the Mississippi River, as well as in several states west of the Mississippi. Eastern subterranean termites are abundant in Louisiana where they used to be the most economically damaging termite species in the state until the invasive Formosan subterranean termite species took its place around 30 years ago. It is well known that Formosan subterranean termites are non-native insects in the US that likely arrived at a Texas port from ships that departed Southeast Asia immediately after World War Two. Today, Formosan termites are by far the most destructive wood-infesting insects in Louisiana where they inflict hundreds of millions of dollars in property damage each year. Residents of the state need no introduction to Formosan subterranean termites, but few residents are aware that Formosans are not the only non-native termite species that frequently infest homes in Louisiana.

Formosan subterranean termites were first discovered in the US back in the 1950s when colonies were recovered from the ground soil and within dead trees near a Houston shipping port. During the next three decades, very few homes were documented as becoming infested with Formosan termites in the country, which led experts to believe that the species had been unable to survive within a foreign environment. However, the unprecedented destruction caused by Formosan termites in New Orleans within just a few short years during the 1980s proved that these non-native insect pests had established an invasive habitat in North America for the first time. While Formosan subterranean termites are certainly destructive in Louisiana, the state is home to eight other termite species that infest homes frequently in the state. Just like Formosan termites, the non-native west Indian powderpost termite species was inadvertently transported into the US via maritime trade routes sometime before 1919. This drywood termite species can be found in the southeastern US, and they cause much destruction throughout Louisiana.

The west Indian powderpost termite, while certainly exotic, is not strictly categorized as an “invasive” species in Louisiana. Generally, in order for a non-native insect species to be considered invasive, a species has to cause some degree of ecological harm within a new and foreign habitat. For example, red-imported fire ants are invasive in the southeast US because they are not native to the region, and they displace native insect populations and destroy native plants that are essential for maintaining ecosystem balance. Formosan subterranean termites are invasive in the subtropical Gulf Coast region of the US because they cannot be eradicated from areas where colonies have already been established, and they displace native termite species, such as the eastern subterranean termite. Two other termite species in the state, midwestern subterranean termites and western drywood termites, are not technically native to Louisiana’s ecosystem, but they are native to nearby states. Since these two species do not have a negative effect on Louisiana’s natural environment, they are considered merely “non-endemic” species in Louisiana as opposed to invasive species.

Have you ever encountered a termite swarm more than once within a week?