Residual barrier treatments are designed to provide extended protection against adult mosquitoes to enhance outdoor comfort. Different from aerial treatments, these treatments are applied by CMCD field technicians at your home and remain effective for up to six weeks. These treatments are currently only available in Port of the Islands and Keewaydin.
Ae. taeniorrhynchus come off the coast in large broods and can travel up to 60 miles at the adult stage from Collier’s state and federal public lands. Because CMCD typically does not perform mosquito control on public lands, this makes it difficult to target this species at the source. Instead, this species must be targeted at the adult stage upon entering populated areas.
Areas like Port of the Islands and Keewaydin Island are especially susceptible to this species due to proximity to their breeding areas. The barrier treatments offered by Collier Mosquito Control District help repel and kill this species in areas where traditional mosquito control practices aren’t practical.
While this species can make being outdoors unbearable due to its aggressive biting, it is not known to pose a disease threat.
CMCD is working with the Port of the Islands Community Improvement District to provide this service to Port of the Island residents. To opt out of barrier treatments, please click here. If you are a resident of Keewaydin and would like to receive barrier treatments, please contact our office at 239-436-1000.
To learn more, please see the “Frequently Asked Questions” below.
Frequently Asked Questions (FAQ) About Residual Barrier Treatments in Port of the Islands and Keewaydin Island by Collier Mosquito Control District (CMCD)
What is a residual barrier treatment?
A residual barrier treatment is a method used to control adult mosquitoes by applying a small amount of insecticide to specific areas where mosquitoes are likely to rest during the day, such as shaded vegetation and other outdoor surfaces. CMCD uses a product called Wisdom TC Flowable, which contains bifenthrin as the active ingredient. Bifenthrin is a synthetic version of natural compounds called pyrethrins, which are found in chrysanthemum flowers. This ingredient works by both killing and repelling mosquitoes.
Why is CMCD offering residual barrier treatments in Port of the Islands and Keewaydin Island?
In 2023 and 2024, CMCD launched residual barrier treatments, beginning with a pilot project on Keewaydin Island to target salt marsh mosquito populations. Using Wisdom TC Flowable, CMCD observed significant effectiveness when the insects came into contact with treated vegetation. Following the success of this pilot, the District is expanding the program to include residents of both Keewaydin Island and Port of the Islands. Similar to Keewaydin Island, the proximity of Port of the Islands to extensive public conservation lands presents unique mosquito management challenges. In such settings, targeted treatments within the community, such as residual barrier applications, are often the most effective and environmentally responsible method of control.
What types of mosquitoes will CMCD control with residual barrier treatments?In Port of the Islands and Keewaydin Island, the primary target of residual barrier treatments is the black salt marsh mosquito, Aedes taeniorhynchus. This mosquito is an aggressive day biting mosquito that is most active in the months of May, June, and July. While Wisdom TC Flowable is effective against a wide range of insect pests, CMCD’s application is carefully focused on controlling mosquitoes that affect outdoor comfort and public health.
How long do CMCD’s residual barrier treatments remain effective?
Bases on studies conducted by CMCD on Keewaydin Island, Wisdom TC Flowable treatments typically remain effective for about 4-6 weeks, depending on factors such as weather conditions, rainfall, and the amount of vegetation in the treated area.
Are CMCD’s residual barrier treatments safe for people, children, and pets?
Yes. The products used are approved by the U.S. Environmental Protection Agency (EPA) for indoor and outdoor pests and are applied by trained professionals following strict safety guidelines. Once the treatment has dried, usually within 30 minutes to an hour, it is safe for people and pets to return to the treated areas. CMCD will post clear signage for residents to inform them when it is safe to enter treated spaces. You do not need to leave your home during our treatments.
What impact do these treatments have on pollinators and beneficial insects?
Wisdom TC Flowable is a broad-spectrum insecticide that is labeled for controlling a variety of insect pests and can be toxic to pollinators and other beneficial insects. CMCD takes special precautions to minimize the impact on pollinators like bees and butterflies. Treatments are applied to vegetation where mosquitoes rest, not to flowers or blooming plants where pollinators are active. Pollinator and butterfly gardens will be avoided. Treatments will only be made when wind conditions are less than 8 mph to ensure accuracy and to avoid drift of the insecticide. If you have registered beehives in the proposed treatment area, please contact our office at 239-436-1000 to notify us of their location so we can take additional protective measures.
What impact do these treatments have on fish and other aquatic wildlife?
Wisdom TC Flowable is toxic to fish and other aquatic wildlife. To protect these species and surrounding conservation lands, CMCD follows strict safety measures during applications that exceed regulatory standards. Treatments are never applied within 10 feet of storm drains or within 30 feet of aquatic habitats such as lakes, ponds, streams, marshes, estuaries, or commercial fish farms. Applications are also scheduled during calm weather conditions when no rain is expected for at least 24 hours and the wind is less than 8 mph. This helps prevent pesticide drift or runoff into sensitive aquatic habitats.
What is the environmental impact of CMCD’s barrier treatments?
Environmental responsibility is a key focus of CMCD’s mosquito control efforts. All treatments are carefully targeted to reduce exposure to non-target species. Residual barrier treatments are not performed in state and federal public lands, helping ensure these natural areas remain undisturbed. CMCD strictly follows state and federal environmental regulations and applies products in a way that supports overall ecological health.
I live in Port of the Islands; can I choose not to participate in the residual barrier treatment program?
Yes. The effectiveness of residual barrier treatments increases when more properties in the community are treated. Your participation plays an important role in supporting a more comprehensive and successful mosquito control effort. However, because these treatments fall outside of CMCD’s general workplan and are being offered specifically to Port of the Islands residents, participation is entirely optional. Since the treatments involve applying products to vegetation and surfaces on private property, CMCD is offering residents of Port of the Islands the opportunity to opt out. If you do not wish to participate, you may fill out the OPT-OUT FORM or call our office at 239-436-1000 to be added to the opt-out list.
Please note: While the District does have a special consideration policy, residents generally cannot opt out of treatments included in CMCD’s general workplan. These routine operations include community-wide surveillance, source reduction, biological control, ground larviciding, and both ground and aerial adulticiding.
I live on Keewaydin Island and would like to receive residual barrier treatments; how can I get on the treatment list?
Residual barrier treatments on Keewaydin Island are available only by request, as they are performed on remote private parcels. To be added to the treatment list, please contact our office directly at (239) 436-1000. Our team will be happy to assist you in scheduling and answer any questions you may have about the service.
I don’t live in Port of the Islands or Keewaydin Island, can I receive residual barrier treatments?
At this time, residual barrier treatments are only available to residents of Port of the Islands and Keewaydin Island. These areas present unique mosquito control challenges due to their proximity to large expanses of state and federal public lands, which limit some of our treatment options in our general workplan. As a result, residual barrier treatments have been prioritized for these specific communities.
We appreciate your interest, and as the program continues to grow, we hope to expand treatment options to additional areas in the future. Please stay connected with our District updates for any changes to service availability.
If you have any other questions about barrier treatments or other methods of mosquito control, please email us at info@cmcd.org.
