Pests take huge bite: $200 a person in Keys
Chalmers Vasquez knows a lot about mosquitoes. He’s been working to keep them under control in South Florida for 20 years.
He knows it’s going to be a bad year when months of drought are followed by lots of rain. Add some high tides and strong easterly winds and you’ve got mosquito trouble, he says.
“Every few years, the mosquito population seems to spike,” Vasquez said in a telephone interview. He’s operations manager for the Mosquito Control Division of Miami-Dade County.
Florida spends more than $160 million a year on mosquito control. Miami-Dade coughs up $2.5 million a year in the mosquito war, or about $1 for each of its 2.5 million people. It is far from the most heavily invaded county in Florida. That distinction belongs to Monroe County, which spends about $200 a person. Monroe, which encompasses the Florida Keys, has about 100,000 people and spends about $20 million a year on mosquito control.
Because tourism is the state’s main industry, Florida would suffer economically without adequate mosquito control, Vasquez said.
Florida’s 45 types of mosquitoes are the most troublesome in June about 10 days after the start of the four-month rainy season. Black Salt Marsh mosquitoes, Florida’s most common ones, are vicious biters and develop from larvae to adult in as little as a week. In 2005, the most active Atlantic hurricane season in history,Vasquez’s office got more than 10,000 calls in one month alone for help against mosquito invaders. It takes about a week of rain before the soil is wet enough that water stands on the land and the Black Salt Marsh mosquito begins breeding. They lay eggs on damp soil usually at the edge of marshes and swamps. The eggs often lie dormant for up to a year. When rains and flooding start, millions of mosquito eggs hatch. “The population explodes,” Vasquez said.
One of the big breeding grounds for Black Salt Marsh mosquitoes is the Everglades. A strong wind can carry swarms up to 20 miles from the Everglades swamps into some of the largest cities. Federal law prevents spraying in the Everglades, so mosquito fighters can’t attack them until they reach homes.
Close in numbers behind the Black Salt Marsh mosquito in Florida is the Aedes aegypti, known as “container breeders.’’ They multiply from stagnant water in pots and buckets and old tires around homes and businesses. They are black with distinct white markings on their legs and chest.
Vasquez’s team of 20 people combat mosquitoes year round. They put most of their effort into getting rid of the “container breeders.’’ He sends out crews on spray trucks and individuals with portable foggers strapped to their backs.
The mosquito fighters also attack largely infested areas from the air. The air war is carried out by Air Force crews flying four-engine, Hercules C-130 aircrafts, workhorse cargo planes that are used for spraying operations around the world. The planes sweep low – often within 250 to 300 feet of trees and mangroves – spewing a mixture of an oil-based insecticide called Permethrin and a water-based insecticide called Aqua-anvil. Mosquito experts say Aqua-anvil does no harm to people and the environment, but say excessive exposure to Permethrin can burn the skin.
The Air Force crews, working with Vasquez’s specialists on insecticides, do most of their Miami-Dade spraying along the mangrove-thick shoreline of Biscayne Bay from just north of Key Biscayne to the southern reaches of the county, a swath of nearly 27,000 acres. They often operate in the middle of the night when most people are asleep.
Years ago, mosquitoes in Florida carried yellow fever, dengue fever and malaria. The diseases have long since been eliminated in Florida. But in recent years, some cases of dengue fever have been reported, and health officials are trying to determine their origin and whether a serious threat is developing.
When Vasquez’s mosquito fighters go out to a home where mosquito trouble is reported, they often see the problem immediately.
“You get to a house, you look around the yard,” he said. “You see a flower pot, and the saucer at the bottom has water in it, breeding mosquitoes. I guess they don’t know that the mosquitoes need standing water to breed. They don’t see it like that. They call mosquito control.”