...From the pages of Agricultural Research magazine
Operation Full Stop 2003:
In New Orleans' Jackson
Square, technician Amelia Mims
(left) and biological science
aid Sarah Joyce, of the Formosan
Subterranean Termite Unit, use
an acoustical detection device
to evaluate termite infestation
In New Orleans, it starts during the twilight hours in late April. Thousands of tiny, winged termitesalatesbegin swarming lampposts.
In some areas, the air becomes so thick with the flying pests that
streetlights dim behind hovering brown clouds. As the alates mate and
drop their wings, the street crackles underfoot.
New Orleans, Louisiana, can reasonably be called the termite capital of the continental United States. It has been overrun by Coptotermes formosanus, the Formosan subterranean termite. Experts believe that the stowaway species entered the country on ships sailing back from the Pacific after World War II. Since their arrival, these termites have multiplied exponentially in the moist, warm, southern Louisiana climate. They've also established themselves in 10 other states and cost U.S. consumers $1 billion every year in control costs and damages.
In 1998, the Agricultural Research Service, with several major cooperators, launched a national campaign to reduce the population of these voracious invaders and lower their cost to society. Now, the researchers are taking stock of the progress they've made and focusing on new endeavors.
Part of a Formosan subterranean
termite nest showing the
extensive system of galleries
the insects create. The nest
was found in an apartment
wall in the New Orleans
No Quarter for Termites in the Vieux Carré
New Orleans' historic French Quarter is the epicenter of the Formosan
infestationa worst-case scenario come to life. Many buildings
in this part of the city contain wood that dates back a century or more.
And the city itself gets about 60 inches of precipitation annually.
With an abundant food supply and a ready source of moisture, Formosan
colonies have been able to increase and expand here over the years.
Exacerbating the problem? Construction practices and a defensive, protect-the-structure approach to termite control made traditional chemical treatment difficult. So near-perfect conditions for termite colonies, combined with limited effective pesticides, contributed to rapid population growth in the late 1980s.
Formosan subterranean termites
feeding on spruce (left) and
birch wood blocks.
By the mid-1990s, the U.S. Congress saw that without some type of intervention to contain the Formosan scourge, many properties within the world-famous Vieux Carré would be reduced to the lacy grillwork they're so famous for. Now, 5 years after Operation Full Stop began, the situation doesn't seem nearly as dire. It looks as though Formosan populations can be managed. The program's coordinators stress one of the most critical lessons they have learned from their research: the importance of having an offensive, areawide management approach.
"Areawide management is key," says Alan Lax, leader of ARS'
Formosan Subterranean Termite Research Unit at the Southern Regional
Research Center (SRRC) in New Orleans. "We've been able to reduce
termite numbers in the French Quarter because we're treating entire
blocks, not just individual homes or businesses."
Frank Guillot, ARS' Formosan termite program coordinator, concurs. "We've been keeping track of alate numbers inside and outside the treatment zone since 1998, the year we began the program. In 1998, about 70 percent as many alates were captured inside the treatment zone as were captured outside. By 2002, that number had been reduced to 42 percent." Visual inspection of easily accessible areas of structures in the French Quarter since the beginning of the program indicated no evidence of newly active termites or the damage they can cause. But advanced technologiesinfrared, acoustic, and motion-detection devicesare now being used to search for termites or their damage in areas not readily accessible.
In studies to determine whether
changes in diet trigger termite
aggression, technician Christopher
Florane (left) and entomologist
Ashok Raina discuss gas
profiles of termites fed different
types of wood.
| Dennis Ring, an entomologist
with the Louisiana State University Agricultural Center (LSU AgCenter)
and principal investigator of the French Quarter program, explains that
instead of applying repellent chemical barriers around buildings, participants
are having baits or nonrepellent liquid termiticides installed around
their properties. They're "playing offense" against the termites
instead of defense, and it's working.
Encouraged by the program's success, researchers expanded the original
15-block treatment zone in 2002. Ring says, "Public participation
in the original area is nearly 100 percent. We've moved out one block
in all directions, so now we're covering close to 30 blocks. We've already
got 60 percent of the properties in the expanded area into the program,
and people continue to join up."
Says Lax, "Before Operation Full Stop began, there was this pervasive myth that you shouldn't pay for commercial termite treatments because they don't work. In fact, only 15 to 20 percent of the properties in the French Quarter had undergone any type of termite prevention program.
Formosan termites can infest
railroad ties like this one.
Termite Board entomologist Janet
McAllister inspects a tie for
termites and nests in New Orleans.
"We've shown property owners that termite treatments can be effective under the right conditions. Our latest estimate is that even outside our treatment zones, where homeowners receive no help from the program, 40 percent of the properties have undergone some type of treatment."
Having access to highly sensitive instruments that can pinpoint exactly
where the termites are hiding is an important aspect of the offensive
strategy. Jack Leonard of the New Orleans Mosquito and Termite Control
Board (NOMTCB) has been using one such instrument in the field for several
years. It's a thermal imager that can detect termites behind walls and
in other hard-to-reach places. The late Bob Melia, who owned Real Time
Thermal Imaging, helped develop the application. He died in 2001, but
his family has continued running his business. Leonard uses the technology
to evaluate different termite control projects sponsored by Operation
Full Stop. Most recently, he checked schools in the Orleans Parish where
control treatments took place.
"The thermal imager is a handheld device about the size of an 8-mm camcorder," explains Leonard. "It takes practice and experience in the field to read the black-and-white images, but we've had good success in detecting infestations. We hope to train more people to use it."
Cottony mold, Paecilomyces
fumosoroseus, is proving very
effective as a natural termite-
control agent. ARS microbiologists
Mark Jackson and Maureen
Wright observe Paecilomyces
cultures before exposing termites
to the fungus.
SRRC entomologist Weste Osbrink and Richard Mankin, an entomologist at ARS' Center for Medical, Agricultural, and Veterinary Entomology in Gainesville, Florida, have been focusing on a different type of technology to uncover termite infestationsacoustics. Osbrink is a termite expert, and Mankin is an expert at detecting insects by their sounds.
"We worked together to create a device that detects termites through
the sounds they make as they're feeding on wood," says Osbrink.
Although such devices are not yet in widespread use, they have great
potential to help scientists and pest control operators manage the termite
Additional research is being conducted by cooperators at the National Center for Physical Acoustics in Oxford, Mississippi, to develop technology and systems to detect termites or their structural damage.
ARS technician Pete Levy (left)
and LSU Agricultural Center
cooperator Chris Morel inspect
one of many in-ground stations
placed throughout the New
Orleans French Quarter to
monitor the presence and
activity of Formosan
Termite-ators: They'll Be Back?
Researchers involved in Operation Full Stop's Armstrong Park project have helped prove how important areawide management and constant vigilance are. Nan-Yao Su, an entomology professor at the University of Florida, and Matt Messenger, an entomologist with NOMTCB, lead the project.
New Orleans' Louis Armstrong Park covers about 31 acres and sits next
to the north side of the French Quarter. Su and Messenger, with their
cooperators, have been studying the foraging behavior of the park's
4 to 6 native subterranean termite colonies and 14 to 18 Formosan subterranean
termite colonies. In one study, they determined how quickly other termites
would reinvade an area after a single colony had been eliminated. Their
work showed that if untreated, both Formosan and native colonies will
begin to occupy vacated territory within days. Complete reoccupation
by Formosan colonies may take as little as 6 months.
The scientists have just begun a new project. Su explains, "We're trying to eliminate all the termites in Armstrong Park so that we can see where new colonies will take hold. This will help us better understand the ecological succession of termite infestations. It will also help us focus on where future problems may occur in an areawide management approach."
Underground monitoring stations
are installed in New Orleans'
Louis Armstrong Park. Aaron
Mullins, an entomologist with
the New Orleans Mosquito and
Termite Control Board, checks for
termite activity in the monitors.
Prime Target: Termites' Tastebuds
One of the most effective ways of getting rid of a termite colony is
with a toxic bait matrixa combination of materials that the pests
like to eat and a slow-acting toxic agent that ultimately kills them.
SRRC entomologists Juan Morales-Ramos and Guadalupe Rojas are experts
on termite nutritional preferences, and they have created several matrix
Rojas says, "In the lab, we have hundreds of petri dishes filled
with termites, and we use the termites like sensory panelists. We feed
them different nutrient mixtures to find out what they like to eat best."
In October 2002, Rojas and Morales-Ramos completed a 2-year, areawide, bait matrix study in residential Mississippi neighborhoods in Poplarville, Picayune, and Biloxi, at Keesler Air Force Base. The research was done with entomologist David Nimocks, president of Ensystex of Fayetteville, North Carolina. The scientists have a cooperative research and development agreement with Ensystex, and ARS has granted an exclusive license to the company to manufacture the bait matrix. Other collaborators included scientists from Mississippi State University's Coastal Research and Extension Center, including David Veal, head of the center; researchers Christine Coker and Patricia Knight; and research associates Margaret Lockwood and Larry Etheridge.
In spring, alate traps are
placed on lampposts throughout
the French Quarter to monitor
mating Formosan subterranean
termites. LSU Agricultural Center
cooperator Chris Morel (left) and
student worker David Cox inspect
an alate trap.
Mississippi has a growing Formosan termite problem, although populations
there aren't nearly as dense as they are in New Orleans. Using an ARS
bait matrix containing chlorfluazuron, ARS and Ensystex researchers
were able to reduce native and Formosan termite activity by 95 percent
in one test area in Picayune. In a related study, they found that one
of their bait matrices, which incorporates diflubenzuron, was also effective
against red imported fire ants. These pests must be controlled in and
around bait sites because their presence repels the termites. And fire
ants are another major urban pest. Having filed a patent application
on the ant bait matrix, the scientists are currently working with Ligia
Hernandez, product development manager for Waterbury Co., Inc., Independence,
Louisiana, which has applied for a license for its manufacture.
Rojas says that they have started new experiments in cooperation with MSU, Ensystex, Waterbury, and James M. Spiers and Formosan termite personnel at ARS' Small Fruits Research Unit in Poplarville. The goal is to focus even more attention on integrated methods to best control both termites and ants.
Termites vs. Essential Oils and Mold
By studying different plant extracts, entomologist Gregg Henderson at the LSU AgCenter has found compounds that are effective against termites and other insects, including red fire ants, mosquitoes, ticks, and cockroaches. One such compound, nootkatone, is derived from essential oils in vetiver grass.
Formosan subterranean termites
living in railroad ties could
reinfest treated areas of New
Orleans. New Orleans Mosquito
and Termite Control Board
inspectors Gustavo Ramirez
(foreground) and John Stennett
remove monitoring devices to
count termites and score wood
Recently, Henderson and his collaborators have been evaluating how
well compounds such as nootkatone work to protect wood from Formosan
termites. Results have been promising. Henderson says the compounds
seem to affect termites' neurotransmitters and stop their movements.
If further experiments prove successful, these essential oils could
replace chemicals such as copper, chromium, and arsenic currently used
to treat lumber against insect attack.
At ARS' Natural Products Research Unit in Oxford, Mississippi, chemists
are extracting natural compounds from other sources, seeking new active
ingredients that could act as termiticides or form the structural basis
for developing such ingredients.
SRRC microbiologist Maureen Wright has been having good success with
a natural termite control agent. It's derived from a cottony mold called
Paecilomyces fumosoroseus. Wright heard about its biological
control abilities from Mark Jackson, a microbiologist with ARS' National
Center for Agricultural Utilization Research, in Peoria, Illinois.
Jackson had developed an efficient and relatively inexpensive way to
produce large amounts of the fungus to control whiteflies, aphids, and
other agricultural pests. Wright tested samples of the mold against
Formosan termites and came away with impressive results: It killed 100
percent of the termites in less than a week.
Wright has demonstrated that termites exposed to the mold transfer it to other members of their colony. She's also shown that it can be effective in various settings. Retired SRRC chemist Bill Connick helped develop several application formulations. A termite-infested tree, for instance, might require a different application method than a wooden structure. ARS is currently negotiating with a company that wishes to license the technology.
What Makes Termites Tick
Besides developing new methods of termite control, Operation Full Stop
scientists have also been learning more about the Formosan termite's
basic biology. Entomologist Ashok Raina leads a group within the main
termite research unit at SRRC. His group observed and recorded, for
the first time, mating in the Formosan termite. They also discovered
a contact sex pheromone in the female's tergal glandthe first
time such a pheromone has been identified for any termite species.
Recently, Christopher Florane, a University of New Orleans graduate student who has been working with Raina's group, discovered new information about why termite colonies attack each other. He found that the basis of aggression was the type of wood eaten by the termites. Only when two termite colonies feed on two different types of trees do they become aggressive toward each other. Florane's abstract and presentation about his finding won a President's Prize at the Entomological Society of America's national meeting in Fort Lauderdale, Florida, in November 2002. He is currently working with Raina to determine exactly how changes in diet trigger aggression.
Termite Research Chugs Along
Also in 2002 . . . NOMTCB entomologist Janet McAllister began a new
studyin cooperation with Dow AgroSciencesthat may eventually
help the New Orleans termite control zone grow still larger. She and
her collaborators are trying to find the best way to treat railroad
ties that could be serving as huge Formosan termite reservoirs.
McAllister explains, "There are two railroad lines running next
to the French Quarter and the Mississippi River that fall outside the
current Operation Full Stop treatment zone. The railroad ties are treated
with creosote, but where the ties have cracked, termites have invaded
untreated pockets of wood inside."
The termites that live in the wooden ties might eventually move right
back into the areas where other Formosan termite populations have been
reduced. McAllister and her team are focusing on a little less than
a mile of track and have already counted eight separate colonies in
the study area. They plan to test different types of baits and toxins,
placing them at varying intervals along the tracks to see which configuration
works best. She expects the project to last several years.
Edgar G. King, Jr., ARS' Mid South Area director, who's been with Operation
Full Stop from the beginning, says, "I am pleased with all the
cooperation we've received from our partners in the program. Their contributions
have been critical to successes in the Vieux Carré, Armstrong
Park, and south Mississippi. Fundamental research on the termite's biology
and ecology, development of new technologies like the bait matrices
and detection devices, and discovery of new chemical and biological
control agents will all help ensure sustained control of this destructive
pest. Our goal now is to implement these measures throughout larger
areas and eliminate the Formosan subterranean termite as a pest of dwellings
in these treated areas."By Amy
Spillman, formerly with ARS.
This research is part of Arthropod Pests of Animals and Humans,
an ARS National Program (#104) described on the World Wide Web at www.nps.ars.usda.gov.
"Operation Full Stop 2003: Stopping the Swarm" was published in the July 2003 issue of Agricultural Research magazine.