The Four Rivers Vector Control District was formed in 1985 by petition initiative and public hearing procedure in accordance with Oregon Revised Statutes 452.020. The district has the obligation to eradicate health vectors, (organisms capable of transferring diseases) wherever they may exist within the area. At present, the principal concern is to control the mosquito population which are found in large numbers throughout the district.

Mosquito vector control districts are established to monitor and control mosquito populations in order to reduce the risk of mosquito-borne diseases, such as malaria, dengue fever, Zika virus, and West Nile Virus. Four Rivers Vector Control District conducts surveillance to monitor mosquito populations, identify potential breeding sites, and implement control measures such as larviciding, adulticiding, and source reduction to help reduce the number of mosquitos and prevent the spread of diseases.

Our ULV fogging units are mounted on pickup trucks and battery powered. They are designed to operate quietly and be as non-disruptive as possible, especially since we typically fog late in the evening when mosquito activity is highest. The equipment produces a fine mist and a low hum, which may not be loud enough to hear from inside your home—particularly if your windows are closed or there is other background noise.

While your property taxes help fund the district’s operations, our mission is to focus on public health by controlling mosquito populations at the source—typically in wetlands, ditches, and standing water where mosquitoes breed. We do not perform private yard or driveway treatments, as this falls outside our scope and would require different resources, permissions, and liability coverage.

However, we’re happy to provide guidance on how you can reduce mosquito habitat on your property and recommend effective products or strategies for personal protection. Please feel free to contact us with any questions.

Our operations are fully funded through property taxes and are focused on vector control measures within our jurisdiction. We receive funds at a rate of .2895 cents per $1000 of assessed property value. The property tax funds we receive are used to help us manage mosquitos across the entire district, ensuring a healthier and safe community for everyone. Please note individual property treatments are not covered under this tax, as it is designed to fund broader, area-wide pest management strategies that benefit all residents in the district.

While we do not provide on-demand service calls, we encourage residents to report any areas of concern through our designated channels. Your input helps us better understand the needs of our community and ensures that our efforts are targeted where they are needed most.

Mosquitoes thrive in warm and wet conditions. When we have warmer conditions this means that the mosquitoes can emerge earlier and reproduce faster. In the right conditions, it takes a mosquito approximately two weeks to transform from an egg to an adult mosquito.

Mosquitoes lay their eggs in water. Primarily we think of large bodies of water such as lakes, rivers, and ponds. However, mosquitoes can lay their eggs in any water receptacle. You can help reduce the mosquito breeding real estate by making sure you don't have any buckets, cans/bottles, frisbees, or even a shovel left out in your yard that would be capable of holding even a small amount of water as these provide the ideal location for mosquitoes to breed.

We are actively working on the river and other waterways throughout the Four Rivers Vector Control District spraying for the mosquito larvae. We are also actively fogging the neighborhoods in the district to treat the adult flying mosquitoes. Our vector control operations are conducted systematically to ensure the best coverage. If you submit a mosquito activity notification, rest assured that we will address your home or area once we reach that part of our district during our scheduled treatment cycle.

Please note there are requirements set forth by the government that we must follow in order to spray for mosquitoes. We also perform landing counts (how many mosquitoes land/bite during a set period of time) to determine if we need to spray/fog for the mosquitoes. Once the threshold has been met, we will spray/fog for the mosquitoes in specific areas.

DEET-based repellents work best at repelling mosquitoes. They also offer other DEET alternatives that work well such as picaridin which offers a close second to the effectiveness of DEET.

DEET concentrations start out at 5% (provides approx. 90 minutes of protection) and go all the way up to 100% DEET (approx. 10 hrs. of protection). Pick a concentration level that will meet your outdoor activity. The American Academy of Pediatrics says that all family members over the age of two months can use DEET-based repellents with up to 30% concentration with confidence.

Mosquito coils and Therma-Cell brand devices can also help provide some protection. Our favorite mosquito repellent is Proven Insect Repellent, it contains picaridin and is scent-free.

Carbon dioxide is the most universally recognized mosquito attractant and can draw mosquitos in from up to 35 meters away. Once a female mosquito is in the general vicinity of a host other cues can predominate such as body odors (sweat, lactic acid) and even heat. Visual stimuli, such as movement, can also factor into host-seeking.

If possible, schedule your activities to avoid the peak mosquito times - usually dawn and dusk. You should also try to dress in light, loose-fitting clothing.

If you must be out during the dawn and dusk hours make sure to wear a DEET or picaridin-based repellent.

No, mosquitoes live in many different areas and habitats which makes it impossible to find and treat all the areas that they breed. Mosquito control is not intended to eliminate all mosquitoes but to reduce the amount of adult mosquitoes to minimize the possibility of people and animals getting sick from mosquito-associated diseases.

Mosquitoes have an average adult life span that typically lasts 3-6 weeks.

Only adult female mosquitoes bite. Female mosquitoes need the protein found in the blood to produce eggs. During their aquatic stages, the mosquito larvae feed on algae and other small organic matter found in the water.

Mosquitoes go to these cooler, humid shady areas during the daytime to rest and escape the hot dry air that can quickly kill them. Maintaining your yard by cutting down tall grass and weeds will reduce the harborage areas and the number of mosquitoes in your yard.

A vector is a carrier of a disease or infection.

Four Rivers Vector Control only deals with mosquitoes.

Please note: We do not provide on-demand service calls. You can fill out the mosquito activity notification form found on the website or call us at the office. Our office phone is (541) 593-1689.

Our vector control operations are conducted systematically, treating our district from north to south. If you submit a service request, rest assured that we will address your home or area once we reach that part of our district during our scheduled treatment cycle.