Unwelcome Visitors

Thomas Chouvenc, University of Florida

Florida is no stranger to spectacular sunsets, numerous tourist attractions...or invasive pests. The Sunshine State might be the ultimate living, breathing research lab for pest management professionals and entomologists alike when it comes to identifying and combatting invasive pest species.

What makes Florida so attractive to invasive species? The state is particularly vulnerable due to its welcoming climate, extensive tourism and the fact that it is a major commercial hub for importing goods from around the world.

The damage caused by invasive species to goods, crops and plants, and structures in Florida alone runs well into the hundreds of millions of dollars annually, according to research from the U.S. Fish and Wildlife Service.

Although Florida carries a disproportionate burden when it comes to invasive species, researchers, extension agents and pest control professionals say understanding the biology and behaviors of invasive species, as well as what role human activities play in their spread, can significantly reduce the negative impacts of these unwelcome visitors.

An invasive pest making its presence felt in Florida is the Asian subterranean termite. First introduced to the state in the mid-1990s on recreational boats arriving from the Caribbean where the species is widespread, this species of termites was attracted to the moist wood found in and around wood docks and moorings.

The Asian subterranean termite has made a slow progression up Florida’s east coast from Key West, with colonies now identified in Ft. Lauderdale, Boca Raton and West Palm Beach.

The Asian subterranean termite mimics the Formosan termite in its aggressive methods of attacking wood, but there are subtle physical differences between the two species (see box at right). This reinforces the need for PMPs to make a correct identification before designing a remediation program for customers.

Chris Keefer, technical services manager for professional pest management at Syngenta, has studied Asian subterranean termites and says they possess several unique behavioral characteristics:

• Earlier Swarming — Asian subterranean termites typically swarm earlier in the season — February to April — than Formosan termites, which usually appear in May. When one ends, the other usually starts.
• Rapid Population Growth — Since there are few natural predators to slow their growth, Asian subterranean termite populations will grow more rapidly than other subterranean termite species.
• More Damage, More Quickly — With the ability for colonies to grow more rapidly, Asian subterranean termites can also cause damage to structures at a faster pace. The sheer numbers of termites bringing to bear their 24/7 destructive behavior can threaten homes.

“It’s important for PMPs to explain the unique characteristics of Asian subterranean termites, especially the swarm timing, with customers so they can keep an eye out for earlier than normal swarm activity,” says Keefer. “The sooner a PMP knows, the quicker a solution can be provided, and the risk reduced.”

According to the University of Florida, Asian subterranean termite alates are often attracted to porch lights, indoor lights and video monitors, especially when doors and unscreened windows are open.

Alates flying indoors are unlikely to find the moist wood or soil they need to successfully establish a colony and succumb quickly. It is likely, however, that most dispersal flights will produce a few new colonies that could become a threat down the road.

Damage resulting from an infestation can become severe in a relatively short period of time, especially when a structure is invaded by a large, mature colony. Dispersal flights, foraging tubes or damage are usually the first signs of an infestation. An indication of an advanced infestation is the inclusion of nest material (carton) in hollowed wood or existing structural voids.

When it comes to treating for Asian subterranean termites, the use of termite bait stations combined with a liquid soil treatment around the perimeter of the infested structure is recommended. An annual termite inspection should also be performed to monitor for any reinfestation.

TERMITE CREEP. How likely is it that homeowners and PMPs in other areas of the country will see the Asian subterranean termite? Keefer says there is a high likelihood that the species will start appearing in other regions that offer a tropical climate with an abundant supply of humidity and moisture.

“Humans often create the conducive environments for termites to flourish,” says Keefer. “Over-irrigating lawns, planting bushes and shrubs to close to structures, and over-applying mulch to flower beds provide termites with the things they crave the most — moisture and an easily accessible food source.”

And while subterranean termites rarely see the light of day living underground, they can easily “Trojan horse” themselves in railroad ties or pallets that have been exposed to moisture, and unknowingly be transported far from the docks of southern Florida.

“It will eventually move out of Florida, so PMPs operating in areas where there are a high number of termite incidents must stay on top of their game,” adds Keefer.

What is the message to PMPs when it comes to Asian subterranean termites?

Keefer encourages PMPs who encounter an unfamiliar termite to get help with identification through their local extension service or the University of Florida. He says Florida PMPs are challenged constantly when it comes to invasive pests.

“There always are new species of ants or mosquitoes finding their way to Florida, and it is imperative to stay on top of the scientific information coming from the extension service, U.S. Department of Agriculture and University of Florida,” adds Keefer.

Keefer points to an infestation of invasive ticks that was introduced to cattle in Florida by egrets that carried the termites from Cuba.

Sharing information on invasive species with extension agents and university researchers is important so colony spread can be tracked, and so others can learn. Keefer says this is vital to minimizing the spread and damage these destructive pests can deliver.

“Be prepared to do some research and have your facts before you talk with customers about the Asian subterranean termite,” says Keefer. “Don’t guess or assume.” — Jeff Fenner