Home Wreckers - Everything you ever wanted to know about Termites (and more)

[Guest guest]

http://www.nolalive.com/speced/homewreckers/index.html

Scientific disagreements flare

Part 2

Some scientists working for competing chemical companies also question how a

chitin-inhibiting chemical could kill the queen termite, since she doesn't

molt. Su says she starves when the termites that feed her die.

Another point of disagreement is whether Sentricon should be used by itself.

Dow wants to establish its baiting system as the primary weapon against

termites and doesn't like its operators to treat with other chemicals when

it uses Sentricon, a recommendation some pest-control operators are

ignoring. They are combining it with new liquid chemical treatments.

Ed , president of Terminix's New Orleans franchise, even is offering

state-approved damage guarantees to those who use that combination, in

certain circumstances.

Block the termites' way in,

send in poison with others

Spokesmen for competing baits say their products are at least as effective

as Sentricon, and claim they work faster because Sentricon doesn't kill

until termites molt. But these baits also have down sides.

FMC Corp. was aware of research by Dow and Su, and knew from its own

marketing data that consumers could be expected to embrace the new bait. But

its system differs from Sentricon in several key ways.

FMC was not convinced that abandoning the chemical barrier was the best

strategy, so it recommends using its baits with either traditional barrier

termiticides or new chemicals that kill termites without repelling them.

The active ingredient in the FMC bait is sulfluramid, a slow-acting stomach

poison less dangerous to humans than Mirex. Like hexaflumuron, FMC's bait is

used in small enough quantities that it poses little hazard to non-targeted

insects and other wildlife.

Sulfluramid disrupts the insect's metabolism, its ability to transform the

energy contained in food into nerve impulses. ''The termite quits feeding,

quits moving, stands around and in a few days dies,'' said Jim Ballard,

pesticides technology manager for FMC.

Workers check the FirstLine monitors, which come in above-ground as well as

below-ground models, every two weeks until termites enter the monitor or

it's clear they are not present. When termites show up, poison bait tubes

are pushed into the ground around the monitors.

Dow's system is based on the notion that termites forage randomly - an idea

supported by Su and some other entomologists - so placing bait stations at

regular, 15-foot to 20-foot intervals is a logical way to assure termites

will find the bait. ''Termites don't forage randomly. They follow moisture

gradients, objects, imperfections.''

- JIM BALLARD,

pesticides technology manager for FMC

FMC follows a different philosophy. Entomologists doing research for the

company, including Louisiana State University entomologist Gregg ,

believe termites follow specific cues in searching for food, and recommend

placing baits in areas where termites are likely to be found.

''Termites don't forage randomly,'' Ballard said. ''They follow moisture

gradients, objects, imperfections.''

Another new entry to the bait war is Ensystex. Its Labyrinth bait uses

another chitin-inhibiting chemical called diflubenzuron. The North

Carolina-based company hopes to get use of the bait approved in Louisiana

this fall, company president Ken Kendall said.

The bait station uses four wooden strips around a hollow monitoring station.

When termites begin eating the wood, the pest-control operator puts the

cardboard bait into the hollow area. Kendall said this approach lessens the

chance that the operator will disturb termites feeding at the station.

But this method also may have its flaws.

One study by Su indicated that while subterranean termites native to

Louisiana would be killed by diflubenzuron, Formosan termites wouldn't eat

such a bait. Kendall disputes that claim, saying his company's laboratory

tests with Formosan termites show they do indeed eat the impregnated

cardboard bait.

Lingering poison disrupts

termite nervous system

Meanwhile, it is Bayer's liquid termiticide Premise that seems to be filling

the gap between baits and the older pesticides: a chemical that comes close

to creating the traditional barrier, and yet works a little like the baits

in killing termites slowly.

Premise disrupts the production of chemicals that make the nervous system

work, just like chlordane. But unlike chlordane, Premise seems only to act

as a poison on insects, not other animals. It also does not give off smelly

fumes like old-style pesticides, and pest-control workers don't need to wear

protective respirators during its application.

Gregg Storey, pest-control marketing product manager for Bayer Corp., said

Premise creates a ''treated zone'' that disrupts the behavior of termites.

They stop eating, feeding others in the colony and grooming each other. When

first applied, Premise is strong enough to kill termites outright. Over

time, as it breaks down, the chemical's behavioral effects cause termites to

be killed by fungus and disease.

''As a colony, termites are very strong, a superorganism,'' he said. ''But

when they're alone and not functioning together, they're pretty wimpy in

defending against infection.''

The company originally hoped it had discovered a potential bait poison, but

soon learned that the disruption in behavior caused by Premise makes it

difficult to guarantee the material will be carried back to the nest by

insects.

© 1998, The Times-Picayune. Used with permission.