There was a gentleman in the Home Depot parking lot one recent Saturday wearing a mosquito-net jacket.
“It really works,” he said with a nod, a wink and two thumbs up. His wife added, “You can get it at Safari Unlimited!”
Safari Unlimited better stock up. According to Dr. Henry Lewandowski, director of Chatham County Mosquito Control (CCMC),
The breeding grounds he’s talking about are the
Sediment brought up from the bottom of the river rises 52-feet into the air in places, reshaping the lowlands’ topography and providing an ideal hatching site for the salt marsh mosquito, a notoriously aggressive species known for assaulting its victims at all hours of the day.
Luckily, Dr. Lewandowski says that salt marsh mosquitoes are not common carriers of the
Dr. Lewandowski estimates that some 100 million mosquitoes emanate from the dredge spoils in a season and from “there inundate the entire county.”
While salt marsh mosquitoes migrate long and far, the mosquito most likely to transmit
Dr. Lewandowski says that his department calls downtown the “Hot Zone.” The exact borders, he says, are the Savannah River to
The Hot Zone is home to nine out of ten cases of
Four years after West Nile was discovered for the first time in the
Hot zone? Sentinel chickens? If this is starting to sound like a full-scale military campaign, it’s not far from the truth. 100 million mosquitoes breeding and striking downtown
War is being waged as Savannahians eat, sleep, work and play. For the most part, we are oblivious to the dangers of living in a war zone, both from the enemy and from the collateral damage inflicted by the weapons used to fight the enemy.
When the Hot Zone “went hot” in 2003 with the first reported cases of
But somehow the Malathion didn’t seem to be working on
The CDC tested mosquito eggs sent from
The timing was inopportune; the Hot Zone was in the middle of a
The Malathion wasn’t entirely ineffective. It worked well on many other kinds of insects, including a small species of wasp that preys on an even smaller insect called “kermes scale.” Without the wasps, the kermes scale population exploded and their food source,
In the spring of 2004, oaks throughout downtown started to turn brown, their limbs withered. The mosquito wars had inadvertently created an entirely different kind of infestation.
Bill Haws, the administrator for
Haws, though careful not to point fingers at Chatham County Mosquito Control, admits that the “pesticides they use are harmful to beneficial insects.” When that happens the “balance of nature gets out of whack,” he says.
In an effort to pop nature back into balance, the City performed its first beneficial insect release, letting go 60,000 predatory wasps in squares and parks all over the Hot Zone.
It seems to have worked, Haws says. In 2005 the oaks returned to a healthy green.
By then Mosquito Control had switched over to a compound called Naled, which is corrosive enough at high volume to take the paint off cars; it is also classified as a reproductive toxin for humans.
When discussing chemicals used in mosquito control, Dr. Lewandowski focuses on the “ultra-low volume” of the pesticide -- one ounce per acre.
“We’ve undergone a real paradigm shift here,” he says. Environmental concerns, cost increases for chemicals, and improving spraying techniques and technology have all combined for a more selective, targeted approach to the application of pesticides.
He continually steers the conversation back to his “biggest problem.” The dredge spoils.
“They never really dry out,” says Dr. Lewandowski, flipping his hands over palms side up on his desk. The top of the dredge spoils dry in the hot sun, then crack, creating thousands of little hatcheries.
The thing about mosquito eggs is that they can lay dormant for months, and then with a bit of water in a deep crevice, you have mosquito magic.
The County keeps two amphibious tractors out at the spoil site, trying to drain water from river bottom sediment by creating ditches and slinging mud around. They douse the area with larvacide mixed with sand in an effort to penetrate the fissures where the mosquitoes breed.
But this technique is imprecise, and resistance to the Methoprene used as a larvacide is always a concern.
While the threat of West Nile is a relatively new danger, the
A headline in the New York Times from the summer of 1984 reads “
Migratory by nature, the salt marsh mosquitoes fan out across the region, snacking on our legs and laying eggs in high marsh. The eggs can lie dormant for years, ready to hatch when a full moon pulls the tide high, creating flood pools where the eggs then hatch off and become larvae.
The primary mosquito vector for
“They absolutely prefer polluted waters,” says Dr. Lewandowski. And once they hatch, they stay pretty close to their breeding ground, primarily urban storm drains, retention ponds, and even sewage treatment lagoons.
The days after heavy rains are busy times for the County’s mosquito control team. Larvacide is dropped into the Hot Zone’s storm drains and over the dredge spoils.
The County’s six entomology experts are busy surveying area waters for signs of larvae populations to treat with Methoprene, a growth regulator, which Dr. Lewandowski credits as being “extremely effective.” But he admits there is “no way we can prevent all adult mosquitoes from hatching off.”
That’s when you’ll hear the rotors of low-altitude choppers and the drone of the fogging trucks.
Much like the Air Force might, Mosquito Control works off of known “target lists” of high-profile breeding areas.
Mosquito Control Chief Entomologist Susan Bruce says newly cleared areas in the county slated for development can be particularly problematic, with the human activity in effect increasing the opportunity for mosquitoes to breed in stagnant water.
“Sometimes they clear the trees and leave big ruts in the ground from the heavy equipment, and that can cause a major, major problem for us. And a lot of that new development is right next to hardwood swamps,” she says.
Hutchinson Island Golf Club and
While Mosquito Control most often sprays the poisons in the evenings around sunset when many of the 38 species of mosquitoes in the County like to dine, they’re also experimenting with different times of day to enhance the dispersal and drift pattern of the pesticides.
Dr. Lewandowski attributes the timing of the pesticide application as a primary reason that there were no reported cases of West Nile Virus in the County last year. Though he also adds that the virus is cyclical in nature and could be on a down cycle. A likely scenario, given that
Outside of the Hot Zone, in
Dr. Lewandowski explains that because the trucks have a closer proximity to people, he prefers not to use Naled like he does aerially in the Hot Zone.
“Naled does tend to sting the eyes briefly,” he says.
The synthetic pyrethroid used is Resmethrin, which is registered with the EPA as a reproductive and developmental toxin. The label for the brand name it is sold under, Scourge, states that it is “highly toxic to fish.”
Dr. Richard Lee of the Skidaway Institute for Oceanography says, “Anytime we mess around with the balance of nature we usually pay a price.”
Dr. Lee says his “concern would be toxicity to shrimp and crabs. Any compound that kills insects, almost always kills shrimp and crabs.”
Then there are the honeybees. Ted Dennard of Savannah Bee Company says, “Anytime they spray, it is a massive loss. By morning there is a pile of dead bees on the ground and dead ones stuck in the hive.”
“Isn’t there something else they can use?” wonders Dennard.
CCMC is already using mosquito fish as a biological control, but the fish are only effective in permanent bodies of water like lakes, some culverts and even ditches. Beginning this year, the county will try a microbacterial larvacide known as Bti. It’s the same stuff in the over-the-counter “Mosquito Dunks” that you can buy at Home Depot.
Bti is the least toxic larvacidal control and has been used effectively for years in mosquito control programs all over the country. Basically it is a bacterium that is toxic only to the mosquito larvae that eat it.
Dr. Lewandowski says the County will try the bacterial larvacide this year for the first time in the Hot Zone’s catch basins, but he is unwilling to commit to its long-term use and says that it is too expensive to use on the dredge spoils.
This year CCMC received much needed reinforcements in their battle against mosquitoes from the state Department of Transportation. They’re kicking in $400,000 for mosquito control in the spoil area, which is over the state border in
When the Savannah River Deepening Project moves forward, new mountains of sediment will appear, making expansive new hatching grounds for the mosquitoes. When that happens, Dr. Lewandowski and his band of fighters will be there with every tractor, truck, airplane, chopper and sprayer they can get their hands on.
And you just might better invest in that mosquito-net jacket. They’re acceptable attire at most local events, at least through Labor Day. ƒç
Stacey Kronquest is a local freelance journalist. To comment, e-mail us at firstname.lastname@example.org
Mosquito Control by the numbers
Total staff: 30
Staff entomologists: 6
Years in current facility: 3
Number of trucks: 5
Number of truck routes: 54
Pilots: 1 -- Scott Yackel is Mosquito Control’s licensed pilot for fixed-wing and rotary wing aircraft. He also serves as helicopter pilot when Savannah Metro Police use one of Mosquito Control’s helicopters.
Helicopters shared with
Though a helicopter is always available for police use, both choppers are owned and maintained by Chatham County Mosquito Control on behalf of the taxpayers.
Annual pesticide cost: $837,000 and rising
Kick it over!
There are 38 species of mosquitoes in
Take the Asian Tiger mosquito, for example. It has a taste for human blood and lays eggs in dark recesses where rainwater can collect.
To avoid becoming an unsuspecting breeder of the Tiger, kick over any container that might contain stagnant water. If you have any desire to sit outside this summer, get out your ladder and clear your gutters.
It’s a nasty job, but when August rolls around, you’ll be glad you did.
When the spray comes down
It can sometimes be unavoidable to prevent pesticide exposure given its wide scale application, but the Public Interest Research Group recommends you try to do the following:
• If you get sprayed, shower immediately. If you believe that you are experiencing symptoms as a result of pesticide exposure, call your doctor or poison control center.
• Keep windows shut and air conditioners off during and after spraying for as long as possible.
• Bring pet dishes, toys, laundry and other portable objects inside.
• Cover outdoor furniture, barbecue grills, sandboxes and play equipment and rinse off surfaces that cannot be covered before use.