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MOSQUITO CONTROL

Four Rivers Vector Control District has different methods of controlling the mosquito population dependent on the life stage of the mosquito. We control both the adult mosquito population and the mosquito larvae.

Mosquito Surveillance

Mosquito surveillance is a comprehensive strategy developed by public health authorities and mosquito control agencies to monitor and manage mosquito populations. 

  1. Surveillance Methods: This involves the use of various techniques to monitor mosquito populations, including trapping, larval surveys, and adult mosquito collections. Traps can be set up in various locations to capture mosquitoes for species identification and disease testing.

  2. Species Identification: Mosquitoes are identified at the species level to understand which species are present in an area and their potential to transmit diseases. This information helps prioritize control efforts.

  3. Disease Testing: Some mosquitoes are tested for the presence of diseases such as West Nile virus, Zika virus, and dengue fever. This helps in early detection and response to potential disease outbreaks. After we have collected, counted, and identified the species, we send them to Oregon State University to test for the presence of diseases.

  4. Control Measures: Based on surveillance data, control measures are implemented to manage mosquito populations and reduce the risk of disease transmission. This may include larviciding, adulticiding, and source reduction.

  5. Community Engagement: Public education and community involvement are important components of a mosquito surveillance plan. When the community is informed about mosquito-borne diseases, how to reduce mosquito breeding sites, and what actions they can take to protect themselves from mosquito bites we can significantly reduce the spread of vector-borne disease.

  6. Monitoring and Evaluation: The effectiveness of the surveillance plan is regularly evaluated to identify any areas for improvement and ensure that the objectives are being met.

Larval Control (Larviciding)

Mosquito larviciding is the process of applying larvicides to kill mosquito larvae before they develop into adult mosquitoes. It is a key component of integrated mosquito control strategies used to reduce mosquito populations and the risk of mosquito-borne diseases. Larviciding is typically done using granular or liquid larvicides, which are applied to mosquito breeding sites such as standing water in containers, storm drains, and other areas where mosquitoes lay their eggs. The timing and frequency of larviciding operations are based on surveillance data, weather conditions, and mosquito activity. 

  1. Identifying Breeding Sites: Four Rivers Vector Control identifies and maps potential breeding sites, such as stagnant water bodies, the marsh land along the banks of the little and big Deschutes Rivers, and other containers that collect rainwater. This helps prioritize larviciding efforts.

  2. Larvicide Selection: Larvicides are chemicals or biological agents that target mosquito larvae. The appropriate larvicide is selected based on the mosquito species present, the type of breeding site, and environmental considerations.

  3. Application Methods: Larvicides can be applied using various methods, including spraying, granular formulations, or slow-release formulations. The application method is chosen based on the size and accessibility of the breeding site.

  4. Monitoring and Evaluation: The effectiveness of larviciding efforts is monitored through larval surveys and mosquito population data. This helps assess the impact of larviciding on mosquito populations and disease transmission.

  5. Environmental Considerations: Larviciding plans take into account environmental factors, such as the impact on non-target organisms and water quality. Larvicides are selected and applied in a manner that minimizes harm to the environment. In Central Oregon we have to be mindful of endangered species such as the spotted frog.

Adult Mosquito Control (Adulticiding)

Mosquito adulticiding is the process of applying insecticides to kill adult mosquitoes. It is a component of integrated mosquito control strategies used to reduce mosquito populations and the risk of mosquito-borne diseases. Adulticiding is typically done using ultra-low volume (ULV) spraying or fogging, which involves dispersing small droplets of insecticide into the air. The timing and location of adulticiding operations are based on surveillance data, weather conditions, and mosquito activity. Adulticiding is often used in conjunction with other mosquito control methods, such as larviciding (treating mosquito breeding sites) and source reduction (eliminating standing water where mosquitoes breed).

  1. Surveillance: Adult mosquito populations are monitored using traps and other surveillance methods to determine the need for adulticiding. This helps identify areas with high mosquito activity and prioritize adulticiding efforts. When mosquitoes reach the threshold of 3 or more mosquitoes in 10 minutes in a specific area Four Rivers may adulticide.

  2. Insecticide Selection: Insecticides are chemicals used to kill adult mosquitoes. The appropriate insecticide is selected based on the mosquito species present, insecticide resistance patterns, and environmental considerations. We use Permethrin mixed with mineral oil at a rate of 1.2 oz. per acre. 

  3. Application Methods: Insecticides can be applied using various methods, including ultra-low volume (ULV) spraying, fogging, and misting. The application method is chosen based on the size and accessibility of the treatment area.

  4. Timing: Adulticiding is typically performed during the evening or early morning when mosquitoes are most active, and the temperature is above 55 degrees. This helps maximize the effectiveness of the insecticide and minimize the impact on non-target organisms such as bees and butterflies. 

  5. Environmental Considerations: Adulticiding plans take into account environmental factors, such as the impact on non-target organisms and air quality. Insecticides are selected and applied in a manner that minimizes harm to the environment.

By implementing a comprehensive mosquito management plan, public health authorities can effectively manage mosquito populations, reduce the risk of disease transmission, and protect the health and well-being of the community.

To report a mosquito nuisance please use the link below.

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