Charleston County Mosquito Control treats larvae in standing water from the air, sprays adults from the ground, runs traps across the county and tests for West Nile, eastern equine encephalitis and St. Louis encephalitis. Its evening truck spraying often does little against the Asian tiger mosquito, which bites in daylight and breeds in containers on your own property.
Key takeaways
- The county treats mosquito larvae in standing water from the air and sprays adult mosquitoes from the ground.
- The county chooses where to spray using surveillance equipment and reports from the public, and it deploys traps across the county.
- The county's surveillance tests for West Nile, eastern equine encephalitis and St. Louis encephalitis.
- The Asian tiger mosquito is the most common daytime-biting mosquito in the Carolinas, and nighttime truck fogging often does not control it.
- Its larvae develop in water held in containers around a home, so emptying and covering those containers is the homeowner's most direct step.
- If mosquitoes persist after breeding on your own property has been reduced, they may be breeding beyond it, and the local mosquito programme is the place to report that.
What does Charleston County Mosquito Control actually do?
The county treats the water where mosquito larvae develop, using treatment from the air, and it sprays adult mosquitoes from the ground. It also runs surveillance so that it knows where to act.
The county's programme works on two fronts. The first is larvae, the immature stage that lives in standing water. Charleston County treats larvae in standing water from the air, which can reach wet areas that are hard to cover on foot. The second is the adult mosquito, which the county targets by ground spraying. Both methods have a place in a county programme, because they reach different stages of the life cycle, and neither one replaces the other.
Ground spraying is the part most people see, usually as a truck moving slowly along a road at dusk. The county posts its aerial and ground schedules on its mosquito control website, so a resident can see when work is planned in a given area. Those schedules describe the programme's work, and they are not a promise about any particular street. For a resident, the useful fact is that the county programme is a shared service with its own methods, and it is not the same as a private treatment of a single yard.
How does the county decide where to spray?
The county chooses targets using surveillance equipment and reports from the public. It deploys up to thirty traps across the county, so the decision is informed by what the traps catch and what residents report.
A county programme cannot be everywhere at once, so it needs a way to decide where to act. Charleston County uses surveillance equipment, including traps deployed across the county, and it chooses targets partly from reports made by residents. That combination lets the programme focus its work on the places where mosquito activity is high or where reports suggest a problem. A resident who reports mosquito trouble is adding to the picture the county uses to decide where to act.
The county takes reports from the public, and residents can point the programme to a problem through its channels. No formal response time is promised for a report, and this guide does not give one. A homeowner who has a persistent problem should report it, keep notes on where and when the mosquitoes are a problem, and understand that the county's response depends on the programme's wider priorities as well as the report.
What do the county's traps and tests look for?
The county tests for West Nile, eastern equine encephalitis and St. Louis encephalitis. Its traps help track where mosquitoes are active so the programme can see patterns across the county.
Surveillance serves two purposes. It helps the programme choose where to spray, and it helps track the viruses that mosquitoes can carry. Charleston County tests for West Nile, eastern equine encephalitis and St. Louis encephalitis. Testing is how the programme knows whether a virus is circulating in an area, which in turn affects how it responds. A test result is a public health signal, and it is one reason the county adjusts its work when conditions change.
Recent public reporting shows the county increasing spraying and surveillance after a West Nile detection in August of this year. Those changes were reported in the press, and the details were attributed to state health department figures and county notices. This guide does not give a case count for Charleston County itself. For the homeowner, the practical point is that the programme's activity can change from one season to the next, and that a change in spraying does not mean the risk in your own yard has changed by the same amount.
Why does a daytime-biting mosquito matter in your own yard?
The Asian tiger mosquito is the most common daytime-biting mosquito in the Carolinas, and it breeds mostly in containers rather than natural wetlands. That means the breeding sites are often on the property itself.
The Asian tiger mosquito is the most common daytime-biting mosquito in the Carolinas, according to Clemson HGIC. Its larvae develop in standing water in artificial containers, including rain gutters, bird baths, flower pots, tyres, barrels, boats, tarps, cans and garden pools. It does not depend on natural wetlands. That is a very different pattern from the marsh mosquitoes that come out after tides and storms, and it means a yard can produce a large number of these mosquitoes without any marsh nearby.
The practical consequence is that the mosquito's home is often the homeowner's own property. A bucket that holds rainwater for a week, a clogged gutter or a saucer under a plant can each be a breeding site. The county's work reaches the wider area, but the yard is the place where a resident has the most direct control. Understanding the Asian tiger mosquito's habits is the key to working out which problems are on the property and which are coming from elsewhere. The mosquito control page covers the professional side of that work.
Why does nighttime truck spraying often miss it?
Clemson HGIC says nighttime truck fogging often does not effectively control Asian tiger mosquitoes, because they are mainly active in daylight. The spraying is aimed at a different time of day than the mosquito's peak activity.
Truck fogging is a common sight in the evening, and it is easy to assume it protects a yard during the day. Clemson HGIC states that nighttime truck fogging often does not effectively control Asian tiger mosquitoes, because the species is mainly active in daylight. The mosquitoes that bite people in the afternoon are not the ones the evening spray is aimed at, which is why a resident can see the truck and still be bitten in the yard.
That does not mean the county's spraying has no value, because the programme is designed for a range of mosquitoes and conditions. It does mean that a homeowner should not rely on evening spraying to deal with daytime biting mosquitoes in the yard. The most direct step is to reduce the containers that hold water on the property, because those are the sites the Asian tiger mosquito uses, and they are within the homeowner's reach.
What can a homeowner do about breeding sites?
Eliminate the sites that hold water: drain containers, drill or overturn those that must stay outside, and shelter the ones that must be stored. Clemson HGIC also describes Bti products for water that cannot be drained, with limits on where they belong.
HGIC's advice to homeowners is to eliminate breeding sites first. That means draining water-filled items, and drilling, overturning or sheltering containers that have to be stored outdoors. Common sites include gutters, bird baths, flower pots, tyres, barrels, boats, tarps, cans and garden pools. A tarp that pools water after a storm is as much a breeding site as a barrel, and the sites that are easiest to overlook are often the ones that produce the most mosquitoes.
Where water cannot be drained, HGIC describes homeowner products that release the beneficial bacterium Bti. These are described for small containers, tree holes or ponds. HGIC cautions that large bodies of water should be treated only by mosquito control professionals. A homeowner should read the label and follow it, and should not assume that a product for a small container is suitable for a pond or a larger body of water. The mosquito control and salt marsh mosquito control pages explain how the professional side differs.
What is different about salt-marsh mosquitoes?
Salt-marsh mosquitoes come from the marsh and tidal edges, and their numbers rise after tides and storms. That is a different source from the containers in a yard, so the approach to them is also different.
The warm half of the year brings the most mosquito pressure, and the marsh adds to it. Salt-marsh emergences often follow tides and storms, when water flooding the marsh edge gives larvae a new place to develop. Residents close to tidal creeks and marsh edges notice this pattern, and it is one reason the county's programme includes work on the marsh as well as on the land.
A homeowner cannot control the marsh, but can understand when pressure is likely to rise. After a storm or a high tide, expect more mosquitoes near the marsh edge, and be aware that the yard may be affected even when it has no containers at all. The salt marsh mosquito control page describes how the professional approach differs from the work in a single yard.
When should you report mosquitoes to the county or the state?
Report persistent mosquitoes to the local mosquito programme, and report dead birds through the state health department. The state health department notes that mosquitoes that persist after breeding on your own property has been reduced may be breeding beyond it.
The state health department advises that if mosquitoes persist after you have reduced breeding on your own property, they may be breeding beyond it. In that case the step is to contact your local mosquito programme, which for Charleston County is Charleston County Mosquito Control. Give the programme as much detail as you can, including where the mosquitoes are, what time of day they bite and how long the problem has lasted.
The state health department also accepts and tests dead birds submitted by the public, as part of its surveillance for West Nile. Its page on submitting dead birds explains how to do that safely, and it should be read before handling any bird. A resident who has a question about a bird or a mosquito that does not fit the programme's usual pattern can start with the health department, which can direct the question to the right place.
Frequently asked questions
Will the county spray my street this week?
The county chooses where to spray using surveillance equipment and reports from the public, and its schedules are posted on its mosquito control website. A date for any particular street cannot be promised here. Checking the posted schedules is the most reliable way to see planned work. A report from a resident can still help the programme decide where to focus.
Is night truck spraying worth waiting for?
Clemson HGIC says nighttime truck fogging often does not effectively control Asian tiger mosquitoes, because they are mainly active in daylight. Relying on evening spraying to deal with daytime biting mosquitoes in a yard is therefore a weak plan. The more direct step is to remove or cover the containers on the property that hold water.
What is Bti, and where can it be used?
Bti is a naturally occurring bacterium that homeowner products release into water to control mosquito larvae. Clemson HGIC describes these products for small containers, tree holes or ponds. HGIC cautions that large bodies of water should be treated only by mosquito control professionals. Read and follow the label, since the right product and use depend on the water being treated.
Which mosquito-borne viruses does the county test for?
The county tests for West Nile, eastern equine encephalitis and St. Louis encephalitis. Testing helps the programme understand whether a virus is circulating in an area, and that can affect how it responds. Changes in spraying are reported in the press from time to time and are not the same as a risk assessment for an individual yard.
How do I submit a dead bird for testing?
The state health department accepts and tests dead birds from the public as part of its West Nile surveillance. Its page on submitting dead birds explains how to do this safely. Do not handle a dead bird without following that guidance. If you are unsure whether a bird should be submitted, ask the health department before moving it.
Who should I call about mosquitoes in my yard?
Start with the local mosquito programme if mosquitoes persist after you have reduced breeding on your property. For a treatment of your own yard, a technician can be booked through the company, and (855) 974-4733 is answered 24/7. Give a clear description of where and when the mosquitoes bite, and whether containers or marsh edges are nearby. A written note helps whichever service is called.
Sources
- Clemson University HGIC
- South Carolina Department of Public Health
- South Carolina Department of Public Health
This guide is general information for Charleston homeowners, not a substitute for an on-site inspection. Prices are estimates. See our disclaimer.