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‘Perfect storm’ leads to above-normal mosquito activity

By Staff | Jun 23, 2020


While the islands normally see a rise in mosquitoes heading into the rainy summer months, the Lee County Mosquito Control District has been out in full force this year thanks to a few factors.

“Southwest Florida has mosquitoes year-round, but we do have our peaks here in Lee County,” LCMCD spokesperson Eric Jackson said. “It typically starts in May with the real high tides that come in and start flooding the saltmarshes.”

He explained that the saltwater or saltmarsh mosquito lays its eggs in the marshes during the winter months when the ground is dry. As the marshes begin filling with water, the eggs start to hatch.

After a few days, the young mosquitoes turn into biting adults.

“Sanibel, in particular, deals with these biting mosquitoes,” Jackson said.

LEE COUNTY MOSQUITO CONTROL DISTRICT Lee County Mosquito Control District helicopter in landing zone.

A few factors this year, though, have made it worse than usual.

“The problem we’ve had this year, in particular, is we had a severe drought so there were even more parts of the saltmarsh that were dry,” he said, adding that it provided additional breeding ground.

In addition, the normal influx of high tides this year was joined by an onslaught of rain.

“That’s kind of what added to the perfect storm,” Jackson said.

“Because it happened so fast, we’ve been playing catch up,” he added.

LEE COUNTY MOSQUITO CONTROL DISTRICT Thousands of salt marsh mosquito larvae.

Recently, the LCMCD has been conducting larvicide missions almost daily, in addition to nighttime spraying activity and scheduling helicopter sprays during the day to tackle the adult mosquitoes.

Typically, larvicide missions are its primary focus – eradication before the larvae become adults.

“We’ve been doing a lot more adulticide treatments than we normally do,” Jackson said. “It’s a seven-day-a-week operation. We’re working day and night battling these mosquitoes.”

The LCMCD uses multiple methods to survey the population to determine if treatments are needed and what kind, like using inspectors and biologists who visit sites across the islands to conduct mosquito counts. There are stationary traps on the islands that lure in mosquitoes, plus trucks mounted with traps.

“We have all of these data points that we can use,” he said. “It gives us an idea of the population.”

LEE COUNTY MOSQUITO CONTROL DISTRICT Lee County Mosquito Control District inspector searching for larvae.

It also continuously checks for larvae at sites.

“It’s really the consistent surveillance that we do,” Jackson said.

On the subject of helicopter treatments, he explained that it is a common method used on the islands because it enables the LCMCD to access areas unreachable by any other means. He pointed to the J.N. “Ding” Darling National Wildlife Refuge, Sanibel-Captiva Conservation Foundation lands and such.

“Accessing them by air is essential to what we do,” Jackson said.

“That’s the tried and true method of killing a lot of the mosquitoes,” he added.


The helicopters fly low to ensure the granules pierce the canopy and may make aggressive turns.

“Our pilots are highly skilled at what they do,” Jackson said. “To some people it can be alarming, especially if they’re not used to it, but it is absolutely essential for us to do our job.”

The LCMCD also relies on tips from the public to identify possible spikes in the population.

“If they’re noticing an increased problem, it is important that they contact us,” he said.

“In order for us to treat, we have to see that there’s a need,” Jackson added. “It (public tips) particularly help us with the urban mosquitoes.”

Moving into the rainy summer months, the marshes will eventually flood, and freshwater mosquitoes start laying their eggs in the water. The LCMCD shifts gears at that point to tackle the new species.

“They are capable of spreading disease,” he said.

It uses sentinel chickens to help track the presence of mosquito-carried viruses.

While there is little that the public can do to help combat saltmarsh mosquitoes, there are measures homeowners can take to help reduce some of the freshwater mosquito populations in the area.

“An important thing is to really keep up with their properties,” Jackson said.

Drain water from garbage cans, house gutters, buckets, pool covers, coolers, toys, flowerpots or any other containers where sprinkler or rainwater has collected. Empty and clean birdbaths and pets’ water bowls at least twice per week. Protect boats and vehicles from rain with tarps that do not hold water.

“Look for those things that you don’t normally think of,” he said.

Jackson noted that an empty bottle cap can serve as a breeding ground for mosquitoes.

“Anything that can contain water can grow them,” he said.

When outdoors, apply an insect repellent and wear long sleeves. Also be aware of the times of day when mosquitoes are the most active, which is typically early in the morning and around dusk.

“And if you’re noticing a larger than normal issue with mosquitoes, give us a call or go on the Website and make a service request,” Jackson said.

This summer, the LCMCD launched the Fight the Bite campaign. The public outreach effort provides information on how to make a service request, what to do at home, ways to protect pets and more.

“It also kind of outlines what we do in our district to protect the public,” he said.

For more information, visit www.lcmcd.com.

To submit a service request, visit online or call 239-694-2174.