

New Bait May
Prove to Be Fatal Last Meal For Pest TermiteBy Jan Suszkiw October 12, 1999NEW ORLEANS, Oct. 12--An
experimental bait that tempts the termite's taste buds with plant fiber and
other ingredients is earning high marks--but not just from the insect.
U.S. Department of Agriculture scientists
are pleased with early test results showing the bait is quickly attacked by the
termite and can require less pesticide to kill the wood-eating pest. In laboratory trials, the bait required up to 95 percent less toxin than
other bait products to kill off captive termite colonies, report Guadalupe
Rojas and Juan Morales-Ramos, entomologists with USDA's
Agricultural Research Service in New
Orleans. The agency has applied for patent protection on the bait, primarily
designed for the Formosan subterranean termite, Coptotermes formosanus.
In tests, the bait often stimulatedfeeding within two weeks of
deployment. By six weeks, the termite population declined, and by three months
little or no activity was evident. Native to southern China and nearby Pacific islands, the Formosan
subterranean termite was discovered in the southern U.S. during the mid-1960s
at several seaport cities, including New Orleans. Possibly transported there by
ships returning from World War IIs South Pacific theater, the termite
today is established in nine southern states, California and Hawaii. In the
U.S. alone, the exotic pest costs an estimated $1 billion dollars annually in
damage, repairs and control expenses The scientists' research is part of a USDA-led national campaign called
Operation Full Stop, begun
last year to reign in the Formosan termite and minimize its damage.
Conventional control methods call for applying chemical insecticides along a
buildings perimeter. However, such defenses often fail to stop the
Formosan termite. That has forced pest control experts to take the offensive. A
key attack strategy is to deploy toxic baits to eliminate the termite
population. "The trick is making sure the termites quickly find and readily feed on
the bait, along with the impregnated toxins," says Rojas, who is with the
ARS' Southern Regional
Research Center in New Orleans. Moreover, she adds, the toxin must be
slow-acting and not kill the termites too soon. Thats because the pests
need time to distribute the toxin to other colony members by exchanging food or
secretions, such as through grooming, excretion or regurgitation. With that in mind, the two researchers developed an entirely new bait
formula. To do this, they carefully studied the termite's foraging behavior,
feeding preferences, and nutritional needs for growth and reproduction. Early
on, they looked to nature for clues. In decaying wood, for example, they found
natural substances that foraging termites readily consume and carry to their
queen to help with her egg-laying. After identifying the substances, the researchers combined them into feeding
stimulants. They then mixed the stimulants with ground plant fiber, water and
other ingredients that maintain proper texture and moisture. They also designed
a covering for the bait (called a matrix) that maintains an
environment the termites prefer. Standard baits employ wooden stakes and cardboard or paper as carriers for
the toxins. But the new baits ingredients stimulate the
termites to feed--and come back for more. This results in more toxin getting
spread quickly to more colony members, says Rojas, at the ARS' center's
Formosan Subterranean Termite Research Unit. In lab trials there, the bait required less pesticide than standard products
and triggered quicker termite feeding. By six weeks, such feeding had killed
off much of the colony. The scientists used both experimental and commercially
registered pesticides, including diflubenzuron and hexaflumuron. Both these
chemicals disrupt the formation of chitin, a substance comprising the termite's
outer "skin," gut wall and air tubes. Field studies conducted at New Orleans City Park confirmed the
scientists lab findings. In the study, they installed yellow pine stakes
next to the ARS bait matrix. A few weeks later, they checked for termite
feeding damage. The results showed that the termites were nine times more
likely to attack and eat the baits than the pine stakes. This summer, licensed
pest control operators in New Orleans began monitoring seven homes in which the
ARS bait matrix had been installed. Similar trials are also underway in
Florida, Mississippi and Alabama. Rojas says the baits, which contained diflubenzuron, were installed in seven
New Orleans homes last June. Biweekly inspections revealed termite feeding on
the baits as soon as two weeks after their installation. Once that happened,
termite activity declined in about six weeks, mirroring findings in the lab.
The ARS research center where Rojas and Morales work will also install the bait
in several of its buildings as well as around infested trees on the
facilitys property. Like many buildings and trees in the Greater New
Orleans area, the ARS center also has been invaded by the Formosan termite. Scientific contact: Guadalupe Rojas and Juan Morales-Ramos,
Formosan
Subterranean Termite Research Unit, ARS Southern Regional Research Center,
New Orleans, La., phone (504) 286- 4382, fax (504) 286-4419,
[email protected],
[email protected]. U.S. Department of Agriculture | |