Aerial spraying of the the controversial pesticide Naled definitely kills mosquitoes, as it has for decades in the Florida Keys.
Naled also kills bees caught outside the hive along with many other beneficial insects, say Keys beekeepers.
“It’s not a fun sight to find 20 to 30 dead bees below each entrance” to a hive, Key Largo beekeeper Dave Fowler said. “For the beekeeper, it’s a very upsetting thing. For the bees, it’s traumatic.”
Fear of the Zika virus transmitted by the Aedes aegypti mosquito brought Naled back into the news this week, with South Carolina aerial spraying destroying millions of bees at a commercial facility. Protests over the planned use of the chemical to combat Zika, which can cause birth defects in the newborns of pregnant women, erupted in Miami Beach and Puerto Rico. Zika also causes flu-like symptoms.
Naled, approved for use by the Environmental Protection Agency, has long been used by the Florida Keys Mosquito Control District in its efforts to kill adult mosquitoes by aerial spraying.
“It’s definitely a need for us,” said Andrea Leal, interim executive director for the Mosquito Control District. “We apply it in the most responsible way we can, basically as a last resort.”
Since a Zika case was first confirmed in Key West, three additional spray flights using Naled have been flown over the city. The Keys seasonal aerial-spraying schedule elsewhere has not changed, Leal said. Monroe County has had three confirmed cases of Zika, all contracted outside the U.S.
The Mosquito Control District keeps a list of about two dozen Keys beekeepers and calls them before an aerial spraying for adult mosquitoes in their area.
“Naled is highly toxic to bees,” says the Pesticide Information Project, a federally funded study by a coalition of state university extension services.
The call gives keepers a chance to take some protective measures for the hives, which generally are not affected. But worker bees that leave the hives are highly vulnerable. Any contact with Naled, “even a tiny drop on the wing,” is fatal, Fowler said.
“Field bees returning to the hive with any taint are blocked by the guard bees, who fight to the death to keep them out,” he said. “Before a spray, you see the bees happily coming and going. After a spray, it turns into a war zone at the [hive] entrances.”
“The spraying is indiscriminate,” Fowler said. “It kills butterflies and moths and every winged insect.”
“Every time they spray, it kills thousands of bees,” said Isabel Ballestas, a partner in Keez Beez, based in Marathon. “It’s a big problem. People don’t realize what a big problem it is.”
Keez Beez makes an effort to locate its hives near local state parks that receive fewer aerial sprays.
“We need bees to pollinate our native trees like mangroves and white tamarind,” Ballestas said. “We need to be intelligent and find safer [mosquito control] methods.”
“If you ask Mosquito Control not to spray your property when they go by with a truck, they’re very cooperative,” said David Lewis of Florida Keys Honey and Bees in the Lower Keys.
“But when they go out with a plane, that sprays everything,” Lewis said. “The heart of the hive stays alive but it kills all the fliers out in the morning. If the hive is already under stress, that kind of loss can be devastating, without a doubt.”
Aerial spraying, in combination with dropping pellets to kill larval mosquitoes, is the only way to reach remote areas of the Keys, Leal said.
Naled is not considered a threat to humans or pets when used appropriately, the Centers for Disease Control and Prevention said in an August statement.
In the Keys, the district uses three-quarters of an ounce of Naled per acre, Leal said. “It’s important for us to have a product that’s effective on adult mosquitoes,” she said. Naled is also the safest pesticide that the Aedes aegypti mosquito so far has not developed a resistance to, she said.
Fowler said the damage to bees and other insects would be reduced if the aerial spray flights took place “first thing in the morning, as soon after dawn as it’s safe for them to fly.”
“At 6:30 or 7 [a.m.], the bees and everything else are just getting started,” Fowler said. “When I hear them going over at 8 or 9. I know most of the [bees] field force is out and really going at it.”