Hang tight, Collingswood—your mosquito treatment is in the works for sometime this week.
That’s the word from Jack Nunemaker, inspector ID specialist at the Camden County Mosquito Commission.
“We’re planning something this week, either Wednesday or Thursday night,” Nunemaker says, for a location “over on the border of Haddonfield” and Collingswood.
In terms of nuisance, the biggest problem in the county right now is the Asian tiger mosquito, Nunemaker says. Its aggressiveness is well-known, it can breed in as little as a capful of water—and despite initial reports from Camden County officials, it’s not really the top threat to transmit West Nile virus.
That distinction goes to the Culex mosquito, which Nunemaker describes as “your typical northern house mosquito.” Whereas the Asian tiger mosquito typically will attack mammals, the Culex feeds on birds, making it a likelier carrier of the disease.
“The Asian tiger mosquito has only been in Camden County about 10 years and has only been a problem for the last five,” Nunemaker says. “These guys are biting you in the middle of the day.”
'2010 was a banner year'
Although the pest problem has been particularly nasty this year, “2010 was the banner year,” he recollects.
In that year, the commission found 74 pools of water—not swimming pools, as is sometimes reported, Nunemaker notes—that tested positive for West Nile virus. Only three of those were Asian tiger mosquito breeding pools.
Comparatively, the commission has only identified 41 mosquito breeding pools to date in 2012. Nunemaker believes that the reason this year seems worse anecdotally is due to the aggressiveness of the Asian tiger mosquito.
Another key factor is the dryness of the summer, he says. Dry years tend to be disease years; wet years tend to be nuisance years. Heavy rains provide stagnant pools and puddles in which mosquitoes may breed, it’s true, but the force of a strong downpour is enough to kill a lot of adult mosquitoes. During a drought, mosquitoes tend to live longer and feed more, taking on a lot more blood, which increases the potential for the spread of disease.
Spray 'n' pray
The best natural deterrent for larval-stage mosquitoes are things like fish, dragonflies, and water striders; in the adult stage, birds, lizards, and amphibians can feed on them. But Nunemaker says that other than eliminating standing water pools and the containers in which water collects, chemical spraying is one of the most effective deterrents for adult mosquitoes.
He calls ultrasonic repellents “dime-store novelties” and says the same for bug zappers and herbal ointments. The best preventive in his book is DEET.
“People tend to believe what they want to,” Nunemaker says. “You always have to take it with a grain of salt.”
The pesticide of choice at the county commission is malathion, which Nunemaker describes as “an older chemical” that’s “very safe” and is most often used in less densely populated areas because it has a pungent aroma. In areas where the smell is a factor, the commission uses resmethrin, known commercially as Scourge.
(There is some evidence to suggest that both chemicals, which kill insects by disrupting the function of their nervous systems, can be toxic to pets and humans; however, a significant amount must be ingested for this to occur.)
Still, Nunemaker says, the commission favors a nonchemical approach to pest control whenever possible. The reason stronger chemicals, like DDT, are no longer used, he says, is because they’re persistent beyond their intended window of use and can have a widespread impact.
“It just doesn’t break down,” Nunemaker says. “It lasts forever; thousands of years in the soil. There’s other pesticides that are just as safe and break down. People don’t want to kill butterflies and moths just to get rid of mosquitoes.”
Turn, turn, turn
At this point in the season, the best advice might be to ride out the rest of the summer into the fall. As the weather turns colder, mosquitoes won’t be around as much at night, Nunemaker says.
Although the commission tries to spray somewhere in the county every night, “I don’t imagine we’ll be out there too much longer,” he says.
One final note: those larger bugs that look similar to mosquitoes and which “hang up the sides of walls” and scare people—those are crane flies, Nunemaker says. Although they may be known colloquially as “mosquito hawks” and “skeeter eaters,” they feed on nectar, and are thus harmful neither to humans nor mosquitoes.