(05/11/22) BATON ROUGE, La. — LSU AgCenter urban entomologist Karen Sun says right now is when Formosan subterranean termites swarm and spread their colonies.

The swarm season for this destructive pest starts as early as April and lasts through June, with a peak in early to mid-May around Mother’s Day.

“The Formosan subterranean termite is an invasive species and the most destructive structural pest in Louisiana,” she said.

They were introduced to the continental U.S. from their native range in East Asia via military cargo ships after World War II.

In Louisiana, this insect was first reported in the port cities of Lake Charles and New Orleans, and now it has spread to 42 of the 64 parishes.

“Subterranean termites nest underground and tunnel in soil to search for cellulose-containing materials as food sources, such as dead or live trees, structural lumbers, cardboard and paper,” she said. “The Formosan subterranean termites pose a greater threat than the native species because they form larger colonies, are more aggressive and build above-ground carton nests.”

A Formosan subterranean termite colony can have millions of individuals and cause more damage in less time than native termites.

At this time of the year, termite colonies produce “swarmers,” which are winged adults that fly out of the nest to find mates and sites for new colonies.

After a short flight and dropping the wings, a pair — a female and a male — run in tandem and search for a suitable nesting site with moisture and food.

They mate in their newly dug nest chamber, produce offspring that develop into workers and soldiers, and become the queen and king.

Sun said in most cases, the swarmers simply die if they can’t find the right environment to dig through and build a nest.

“Unlike the native subterranean termites in Louisiana that swarm during the day, the Formosan subterranean termites fly at dusk, and they prefer warm, humid and windless evenings,” she said. “Their swarmers are yellowish-brown in color and are attracted to lights.”

Formosans swarm in such large numbers, and thousands of termites may be seen hovering around a streetlight.

These swarmers don’t cause any damage, but if you don’t take a few precautions, they can spell the beginning of termite problems.

“If you’re seeing swarmers, that doesn’t necessarily mean that you have termites in your home, but it does mean they are in your neighborhood,” Sun said. “In order to keep them away from your home, you need to get rid of any water sources such as leaky pipes and also remove food sources such as mulch contacting the foundation.”

Another thing residents can do during the swarming season is turn off outside lights. Even dimming inside lights will help, as termites are attracted to the light.

“The Formosan subterranean termite is the most costly in the world, and Louisiana is one of the worst-infested states,” Sun said. “This termite loves subtropical areas, so they do really well here.”

Sun said termite swarmers can be a nuisance when they fly in large numbers. But killing the swarmers in or around the house does not provide any protection from further termite activity and damage.

“Protecting your home from termites begins with an inspection by a pest management professional, followed by a proper treatment depending on the situation,” she said.

Because subterranean termites require cellulose and moisture to survive, homeowners can help ward off potential damage by limiting the termites’ food and water sources. Here are several actions you can do to protect your home:

— Turn off outdoor lights at night in May and June to avoid attracting swarmers.

— Remove all wood, cardboard and other cellulose-containing materials from around or under your home.

— Keep mulch 8 to 12 inches from the foundation or perimeter of your home.

— Fix dripping outdoor faucets and repair leaks in the roof or pipes.

— Slope the landscape so water will drain away from the house.

— Use only licensed and certified pest management professionals for termite treatments.

“When termite swarms occur, you can collect some of the insects or their wings so they can be identified by a pest control service or an entomologist,” Sun said.

These specimens can be submitted to the LSU AgCenter Department of Entomology or an LSU AgCenter parish office. For further information, contact Sun at qsun@agcenter.lsu.edu.

Swarming termites attracted to a flood light. They will be swarming through June. There can be thousands around one light. Photo by Qian “Karen” Sun/LSU AgCenter

Wings dropped by swarming termites. Photo by Qian “Karen” Sun/LSU AgCenter