With mosquito counts on Miami Beach rebounding over the Labor Day weekend, Miami-Dade officials announced on Tuesday that they will begin aerial spraying of the pesticide naled in South Beach this week — a move certain to draw political opposition from some city leaders.
Spraying is scheduled to begin at 5 a.m. Thursday between Eighth and 28th streets from the beach to Biscayne Bay, covering much of the zone where mosquitoes are transmitting the virus, county officials said. The plane will fly 300 feet over the ocean and rely on winds to carry the pesticide onto the barrier island. The aerial spraying will continue Sunday morning and two more times during the next few weekends.
The announcement represented a reversal by state officials and the Centers for Disease Control and Prevention, who previously said Miami Beach’s dense urban environment and high-rise buildings made aerial spraying difficult.
County and city officials said the recommendation came down from the CDC, and the state’s Department of Agriculture and Department of Health after mosquito counts increased during the holiday weekend. Gov. Rick Scott gave the order Tuesday.
“This is the right and safe thing to do at this time,” Miami-Dade Mayor Carlos Gimenez said in a written statement.
The Beach commission will meet Wednesday morning for a workshop on naled. One commissioner, Michael Grieco, called for a special commission meeting after the workshop to make sure elected officials can take action if needed.
Last week, Grieco drafted an ordinance opposing aerial spraying after he said constituents had expressed ardent opposition to it.
“It’s not something that’s going to be welcomed here in Miami Beach,” Grieco said on Friday.
But Zika is also an unwelcome guest in Miami Beach, the heart of the region’s tourism industry.
Early Tuesday morning, the county’s mosquito control department deployed specialized trucks to spray larvicide in areas of Miami Beach. The Buffalo Turbine trucks targeted breeding areas with Bti, which kills the larvae of mosquitoes, fungus gnats and blackflies.
Truck spraying is scheduled to continue over the next four weeks during early morning hours, targeting the area west of Washington Avenue between 2 a.m. and 6 a.m., and the area east of Washington Avenue between 5 a.m. and 6 a.m. approximately every seven days.
Intensive spraying and other efforts to reduce mosquito breeding have been under way since health officials identified a section of Miami Beach as an active Zika transmission zone on Aug. 19, about three weeks after they said mosquitoes were spreading the virus in a one-square-mile area of Miami’s Wynwood neighborhood.
On Sept. 1, state officials announced that mosquitoes in the city had tested positive for Zika — the first such find in the nation. The state’s agriculture department said three of 19 mosquito traps placed throughout the 1.5-square-mile area of Miami Beach had caught Zika-positive insects.
But health officials identified only one trap location: Miami Beach Botanical Garden. The state has refused to identify the other two areas in Miami Beach where traps with Zika-positive mosquitoes were located, citing Florida statutes governing the sharing of confidential or exempt information and epidemiological investigations.
Prior to the holiday weekend, mosquito counts in Miami Beach had dropped by 64 percent between Aug. 21 and Sept. 1, according to county officials, who attributed the reduction to a combination of spraying by trucks and hand-held devices, removal of bromeliads (which hold their own water supply) and other efforts to reduce breeding grounds for the insects that are spreading Zika.
County officials reported finding about 36 mosquitoes per trap on Aug. 21 and an average of 13 on Sept. 1. And although they had seen some traps with counts as low as four and six mosquitoes, they said heavy rains likely reduced the numbers of insects caught in the traps.
Aerial spraying in Miami Beach will not follow the same program applied in Wynwood, where county officials used two different pesticides — one that takes out adults, the other that kills mosquito eggs and larvae.
The program in Miami Beach will target only adult insects. Truck spraying and mosquito inspectors carrying hand-held foggers will continue to work on the ground to target larvae and eggs.
Gimenez said on Tuesday that aerial spraying in Miami Beach will include four cycles of pesticide to kill adult mosquitoes.
“We will keep the number of adulticide missions to a minimum on school days, and parents may prefer to keep students indoors until 6:30 a.m. following aerial spraying,” the mayor said in a written statement.
After being briefed on the plan and speaking with the county, Miami Beach Mayor Philip Levine told the Miami Herald that he wants to know more about what potential effects the spraying may have on residents.
“My job is to keep residents safe and informed,” he said. “We want the governor and officials to tell us and the people what they know about what, if any, are the ramifications of this.”
Lee Casey, senior division director for Miami-Dade’s solid waste management department, said the naled-based insecticide dissipates when it hits water and moisture in the soil.
“It doesn’t persist in the environment,” he said in an interview Thursday. “It is inactive when it hits the water.”
He said the county’s contractor, Dynamic Aviation, has used this type of “offset spraying” before, where pilots use meteorological data to calculate a flight path that will ensure winds carry the spray over the target area.
The spraying would be rescheduled if wind conditions weren’t right.
Controversy over the use of naled has persisted in the wake of the spread of Zika. Residents of Puerto Rico, an island hit hard by the Zika outbreak, have protested the use of the insecticide. A U.S. Fish and Wildlife Service study found that chemicals used to combat mosquitoes are toxic to butterflies. Last week, a few beekeepers in Dorchester County, South Carolina, lost millions of honeybees when they died after aerial spraying of naled. In this case, the county had failed to notify the beekeeping community of the spraying beforehand.
On Thursday, Miami-Dade and Beach officials said they were left with no choice after mosquito counts increased and the governor accepted the CDC’s recommendation to spray from the air. The county has notified one beekeeper in South Beach to prepare for the spraying by placing wet burlap over the hives so the naled dissipates when it hits the moisture.