South Miami Mayor Philip Stoddard doesn’t care much for mosquitos, but he doesn’t want the spraying of them to kill butterflies and a rare Florida bat.
He and his fellow city commissioners agreed Tuesday to redefine the city’s designation as a “wildlife sanctuary.” By doing this, the commission puts the Miami-Dade County mosquito control divison on notice — that it cannot spray broad-spectrum insecticides or biocides within the territorial limits of South Miami, just south of Coral Gables.
Commissioners also voted Tuesday on a related resolution calling for the city and the county’s mosquito control district to negotiate a mutually agreeable plan for controlling mosquitos here.
The commissioners took their second vote Tuesday night. The measure now becomes law in South Miami.
“We've got ourselves a scientist here,” Commissioner Bob Welsh said as the measure passed unanimously. “We better listen to him.”
Stoddard, a biology professor at Florida International University, said the city’s action is important to keep insecticides from destroying the food supply of the state’s rare mammals and insects, including the Florida bonneted bat. According to Stoddard, Miami-Dade County’s mosquito control division is spraying to kill adult-female salt marsh mosquitos; the toxins in the spray destroy the food supply for young bats.
“This ordinance provides us a tool to negotiate with mosquito control,” he said.
“In June, that’s when the young fledge [develop their wings to fly],” Stoddard said. “They are dependent on a large population of moths flying around. That’s the time of year we get salt marsh mosquitos and the mosquito control division of Miami Dade County comes out and sprays for mosquitos and kills them off.”
“[The spray] is somewhere between 400 to 4,000 times more toxic to butterflies than it is mosquitos.”
Research conducted at FIU has shown the insecticides, when used at the concentrations applied for by mosquito control, are deadly to insects such as the Florida atala butterfly, the Monarch butterfly, the Schaus swallowtail butterfly, and other arthropods and pollinators that reside in South Florida.
According to its public works website, Miami Dade County uses the insecticide Naled (Dibrom Concentrate) solely for aerial application. It is “effective in controlling adult salt marsh mosquitos” and is “somewhat irritating if droplets get onto the skin or in the eye,” according to the site.
Friday was the first aerial application of the Naled this year, said Chalmers Vasquez, the mosquito control operations manager for Miami-Dade.
Vasquez said that no aerial application was used last year. By contrast, in 2004, the county sprayed Naled more than 20 times.
“Dibrom hydrolyzes very quickly,” Vasquez said. “Between 24 to 48 hours there is no residue left.”
Spraying is necessary to control mosquitos, Vasquez added.
“We have a number of calls in the area, including South Miami, where the residents are screaming for mosquito control because they are being attacked by mosquitos.’’
There are fewer than 1,000 Florida bonneted bats in existence. U.S. wildlife managers added the bats to the endangered species list in November, after citing habitat loss and mosquito spraying as deadly threats.
Miami-Dade County uses Beechcraft-type airplanes that carry a 100-gallon tank of insecticide. The planes spray every 1,000 feet at 300 feet altitude, according to Vasquez.
Stoddard inquired about stopping the spraying, but was met with opposition.
“They wouldn’t stop spraying,” Stoddard said. “They said that under the Florida statute, they aren’t allowed to stop. I looked up the statute and found a provision in which you can negotiate a more nuanced mosquito control policy.
“It doesn’t make sense to be spraying on a large scale for adult mosquitos,” Stoddard added. “If you’ve got an outbreak of dengue fever in one block, does it make sense to spray around the block at that location and just try to knock it down? Yes it does. If you can nip an epidemic in the bud like that, go ahead and blast it. But to cover half a city, all you are doing is building a resistance.”
Vasquez says that he has not seen any signs of mosquitos building a resistance to the insecticides.
Stoddard cited older methods such as water control and less dangerous chemical approaches as alternatives. One chemical that could be used is Bacillus thuringiensis (Bt), which Stoddard says is not poisonous to most insects.
Vasquez contends the county needs to spray because of the volume of mosquitos blanketing the area.
“We have a high count of mosquitos,” Vasquez said. “We had 5, 10, 15 mosquitos per minute in our trap. That, coupled with the number of complaint calls, triggers the application of pesticide in the area.”
“We don’t apply the pesticides because they’re fun. We wait for the reason to do it.”
According to the Centers for Disease Control and Prevention (CDC), nearly 40,000 people in the United States have contracted the West Nile virus disease since 1999.
The first cases of Chikungunya fever acquired in the United States were reported on July 17 in Miami Dade and Palm Beach counties, according to the CDC. The virus rarely kills those infected but typically causes fever and severe joint pain.
“Having those number of mosquitos, like right now, people are scared,” Vasquez said. “We have cases of disease and we need to protect the people.”
Countered Stoddard: “The problem is that these are not selected for mosquitos, by any means, so they wipe out everything,” Stoddard said. “The insecticides typically knock out the mosquitos leaving the larvae to hatch out and make more. You have really used a big hammer on a small problem.”