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MOSQUITO WARS
A new approach to controlling mosquitoes through marsh management cuts
reliance on spraying and is showing promise elsewhere, but Glynn
County is fighting to keep its old ways.
By DAVID ROYER
The Brunswick News
Bzzzzzz — swat!
Newcomers to Southeast Georgia are just discovering what locals have come
to expect every year around this time.
Clouds of hungry mosquitoes are swarming in the muddy bogs in Glynn
County's lowlands. Other parts of Georgia already have been hit hard by an early wave of
the pests.
To head off the attack this year, Glynn County officials are pushing
forward with the tried-and-true control method they have favored since the
1980s — dredging a series of tidal ditches in two of the main mosquito breeding grounds, on
Little St. Simons and Jekyll islands.
"Those small areas are responsible for about 60 percent of mosquitoes,"
County Commission Chair Cap Fendig said, citing a figure he said the county's mosquito
control division came up with a few years ago.
Fendig returned Friday from a visit with U.S. Rep. Jack Kingston, R-1, who
promised to support the county in its fight to obtain permits to dredge the ditches
from the U.S. Army Corps of Engineers.
But the Corps and some environmental groups say ditching is out of date
and that there may be a better solution to the coast's mosquito woes.
Faced with a difficult battle to gain the permits needed to maintain the
ditches on Little St. Simons and Jekyll islands, county officials and Little St. Simons
Island representatives say the only option is to spray more chemicals on
mosquito-prone marshes – and that is an option that makes no one happy.
"I think this year, they're going have to purchase more pesticides," said
Duane Harris, a former state Coastal Resources Division director now working as a
consultant for Little St. Simons Island, a private island and nature preserve that wraps around
the northeast shore of St. Simons Island.
Harris is supporting the county's efforts to open up a series of dozens of
straight-line, tidally influenced ditches dug at the north end of Little St. Simons
Island some 20 years ago to open up stagnant marshes.
Here is how they work: Mosquitoes lay their eggs in the muddy banks of the
ditches, and when the tide flows out, the eggs go with it.
Fewer eggs mean fewer chemicals are needed to keep populations down.
In the marshes of Glynn County, the ditches tend to fill in with sediment
and need to be cleared out with a rotary ditcher. The last time this
was done was in 2003.
Still, the ditches are a cost-effective alternative to spraying larvicide
from a helicopter over the marshes to kill the eggs, according to the county's
mosquito control director, Peter Taylor.
Spraying can cost up to $20,000 an hour for chemicals alone.
Over 10 years, ditching can provide effective mosquito control for $70,000
less than the cost of chemical spraying over the same period, Taylor said, citing a 1990
study by the mosquito extermination commission in Ocean County, N.J.
Over 25 years, the savings jump to
$630,000.
But others say that mosquito management has evolved over the past 20
years, and newer methods may be able to preserve fragile marshland
while saving the county money in the long run.
"Ditching by itself is not a plan, it is a tool," said Daniel Parshley,
Executive Director of the Glynn Environmental Coalition in Brunswick.
Over the past few years, the county has been forced to obtain emergency
permits to clear out the mosquito ditches when the bugs get bad enough to pose a health
hazard.
This year, the county commission voted to spend $10,000 to hire a
consultant, Register & Associates of McDonough, to persuade Army Corps officials to hand over the
ditching permits. The first meeting could occur as soon as next
week.
Parshley says that money would be better spent developing a comprehensive,
long range plan for mosquito control. "Glynn County fighting a plan shows that they have no interest in saving
money," he said. "Instead, we keep bumbling from emergency to
emergency."
Meanwhile, officials from the Corps have said that they would rather see
the county use a more modern method called Open Marsh Water Management.
Old-style rotary ditching machines created straight ditches and piled mud
up on the side of banks, potentially altering the natural environment, some scientists
believe.
Open Marsh Water Management would plug up some of the existing ditches to
create small pools where mosquito-eating fish would
live. It might also require that some straight-line ditches be dug into more
natural curves.
The technique has been used successfully in the Northeast, but has seen
limited use on the South Atlantic Coast.
In a way, environmentalists say, the techniques are already in use in Glynn
County — in the undisturbed natural areas of the coast, where mosquitoes and their natural
predators are kept in balance.
In 2003, the state Department of Natural Resources Coastal Resources
Division encouraged the county to adopt the new practice while limiting ditching, as part of a
long-term mosquito reduction
plan.
Some open marsh techniques have been used in other parts of Georgia's
coast.
Henry Lewandowski, director of Chatham County Mosquito Control, said that
county has successfully used mosquito-eating fish in some fresh water and brackish
water ponds.
But in Georgia salt marshes, Lewandowski said Open Marsh Water
Management may create problems. "A standing water situation has to be looked at very carefully from a
mosquito standpoint," he said. "If there's a lot of standing grass in that pool,
then mosquito fish may not be able to get around
effectively."
Lewandowski pointed to research suggesting that old straight-line ditches
may actually increase the spread of spartina, the grass that grows in salt-water
marshes.
According to Fendig, Glynn County's unique coastal ecology means the
techniques just won't work here. "We have some unique coastal dynamics that other areas don't have," he
said. "Our average change of tide level is seven to eight feet, where the rest of the United
States is about a foot and a half, at most. That dynamic alone makes it difficult to put
in place the kind of system they're wanting to put in."
Harris added that when the ditches were initially dug years ago, some
contained pools for mosquito fish. They did not work well in Glynn's tidal environment, he
said.
He and Fendig both concede that, even if their fight to obtain permits
from the Corps is successful, it will be next year before any work could get
started.
"I don't know what their problem is, why this is not being approved,"
Harris said. "Nothing has changed, so what's the difference now?"
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