From The Blog

Mosquito Misting Systems

Nobody likes mosquitoes. The KICA Lakes Management Department is responsible for mosquito abatement on the island. Most of Kiawah’s mosquitoes come from the salt marsh, from low-lying areas where water temporarily pools, or from man-made items that hold water. Man-made items include birdbaths, improperly installed or maintained rain gutters, planting pots – basically anything that can hold a tablespoon of water for two weeks.

A relatively new item for private mosquito control that the Lakes Department sees on the island is the “mosquito misting” system. Pest control companies install a series of nozzles and tubing outside of the house and around the yard that dispense pesticide on an automated schedule. Following are some common misconceptions about these systems. Misconception: The system dispenses a mosquito repellant, which is an “all natural chemical.”

The Lakes staff has seen the systems dispense synthetic pyrethrin, a pesticide based on a natural extract from the chrysanthemum flower. While this extract itself is a natural insecticide, it is now synthetically produced and coupled with another chemical (a synergist called Piperonyl butoxide) that increases its toxicity. It is a contact pesticide that kills beneficial insects like honeybees, dragonflies, and butterflies, in the same way that it kills mosquitoes. It is also toxic to fish and shellfish. Consequently, pyrethrin should not be applied in a way that can carry it into water bodies or the marsh.

Misconception: The product is not toxic to humans.

It is true that of all the pesticides on the market today, this synthetic pyrethrin has one of the lowest mammalian toxicity rates. KICA uses a product like this in its mosquito control program for that reason. That doesn’t mean that it is completely non-toxic or that it does not pose potential risks to humans, animals, or the environment. There are label restrictions about applying pyrethrin pesticides and instructions about what personal protective equipment (PPE) should be used when handling them. Always follow the product label’s instructions and heed the warnings to minimize risk of harm.

KICA conducts island mosquito control operations during predawn hours (usually between 4:00 a.m. and 6:00 a.m.) to minimize chances of human contact. Members with misting systems should remain indoors during and immediately after misting. Keep your pets inside during the same period. Synthetic pyrethrin breaks down in sunlight, so care should be taken until this occurs. Do not run your air conditioning (or heating) system while the misting system is in operation to avoid introducing the pesticide into your home.

Mosquito control alternatives to misting The preferred approach to mosquito control is the commonly held practice of Integrated Pest Management (IPM). IPM is an approach that first assesses the pest situation, evaluates the merits of pest management options, and then implements a system of complementary management actions within a defined area. In other words, the actual presence of mosquito populations would be determined before spraying occurs, so nontarget organisms are not affected. IPM also promotes source reduction, or the elimination of mosquito breeding habitats and treatment of mosquitoes in their larval forms. At these stages, mosquitoes are more susceptible to treatment options, and these options are typically less toxic than the products used for adult control. Two of these are Bti (Bacillus thuringiensis israelenis) and methoprene. Bti is a bacterial toxin that infects and kills mosquito larvae. It is safe and environmentally sound because it is highly selective, killing only mosquitoes and black flies. Bti contains no poisonous chemicals and is harmless to other living things. Methoprene is an insect growth regulator (IGR) that stops mosquitoes from becoming breeding, biting adults. It is target-specific as well, and will not affect fish, waterfowl, or mammals.

A mosquito trap is another viable alternative mosquito control method that does not involve the use of pesticides. These devices give off carbon monoxide via a propane tank that attracts the mosquitoes, which are drawn into a bag where they dry out and die. These devices are more environmentally friendly because they only target mosquitoes. They also run 24-hours a day, decreasing mosquito populations whenever conditions are favorable for mosquito activity and not relying on an automated schedule. If you already have a mosquito misting system or decide to purchase one, here are some things to consider:

1) Always operate the system in accordance with instructions and warnings. If a system develops some type of leak or if the underground tubing is cut, the system will dispense pesticide that has the potential to leach into the ground and contaminate groundwater. Thus, always ensure that the nozzles are putting out a normal amount of spray. If not, that may be an indication that there is a leak in the tubing. If you suspect a leak, contact the installation company immediately.

2) Make a contingency plan for spill response. Any container has the potential to leak. KICA stores only 110 gallons of product at any given time for island-wide mosquito control operations. Misting systems range from 55 to 225 gallons. If a container of this size begins to leak, call St. Johns Fire Department, as it is not a cleanup situation that should be attempted by a homeowner.

3) Only use approved products in the misting system. There is often the temptation that something a “little stronger” will really do the job. Using an unapproved product, or using an approved product without heeding warnings and instructions, may turn out to be a violation of environmental laws and regulations, so please use care and protect the environment.

4) It’s best not to program the system to run during daylight hours. One reason is the potential impact on workers. Landscaping, phone, cable, or utility personnel, for example, could be unintentionally exposed should the system go off while they are working. Another consideration is the undue impact these systems have on beneficial or desirable insects. Insects are close to the base of the food chain, so they play an important ecological role in a healthy ecosystem. Many bird, reptile, and amphibian species feed on insects that are active during the day. Running a misting system that negatively impacts daytime insects negatively impacts these other species as well.

5) Be conscious of your neighbors. If it is windy or rainy, shut the system off, and consider installing rain and wind meters that shut the system down automatically. Wind can carry the mist 150 feet, easily reaching your neighbor’s property. KICA does not spray when the wind is above 10 mph to prevent unintended impact to non-target areas. Operating the system during rain can cause the pesticide to wash away, with the likely endpoint being a storm drain leading to a lake or the marsh. Events that result in pesticide leaving your property are potentially subject to fines from the Clemson Department of Pesticide Regulation.

6) If you have a misting system installed, make sure that the pesticide container is locked to prevent tampering or access by children. Also, make sure the pesticide container is secured to prevent it from being dislodged during a tropical storm.

7) Inform the St. Johns Fire Department of the amount of pesticide being stored on your property in the event they have to respond to a fire at your residence.

When considering pest control options, research the available products and optional methods. Educate yourself to the extent possible so you can make an informed decision.