One hundred years of public health work along the Wasatch.
The Salt Lake City Mosquito Abatement District (SLCMAD) has been in existence for over 100 years. Utah was the third state to pass legislation for mosquito control, following New Jersey (1912) and California (1915). When the Utah Senate passed Senate Bill 185 in 1923 authorizing the formation and taxing of mosquito abatement districts, a petition signed by 8,100 registered Salt Lake City voters accompanied it, asking for a district to include all territory within the boundaries of Salt Lake City. The SLCMAD was formed in 1923 and became operational in 1924, making it the first abatement district in Utah and the second outside New Jersey.
The SLCMAD is a local service district with its governing power vested in a five-member Board of Trustees appointed by the Salt Lake City Council. The Board establishes all SLCMAD policies and hires an executive director to run daily operations. Funding comes through property taxes with a certified tax rate. Although the district's jurisdictional boundaries match Salt Lake City's (~110 square miles), the district is also responsible for unincorporated regions of Salt Lake County, encompassing 63 square miles of freshwater wetlands surrounding the Great Salt Lake. These wetlands produce an abundance of Aedes dorsalis and Culex tarsalis mosquitoes, which is why SLCMAD and Utah's other mosquito abatement districts have long been among the leaders in advancing mosquito surveillance and control.
Before the District
Long before subdivisions filled the valley floor, mosquito broods rising from the marshes east of the Great Salt Lake were a force residents endured. Newspapers compared them to "sands upon the seashore." Cattle were "almost wild with pain." Even summer drives required headnets.
In 1919, Utah State Health Commissioner Theodore Beatty wrote to the US Surgeon General requesting federal assistance with what he described as Utah's "perplexing" mosquito problem. Three years of advocacy followed before the legislature acted.
Founding Years
1923 — Senate Bill 185
Governor Charles Mabey signs legislation authorizing mosquito abatement districts in Utah. A petition signed by 8,100 Salt Lake City voters accompanies the bill.
1924 — First Board Meeting
On May 19, the trustees meet for the first time. Their first task was figuring out what could be done so late in the season. They authorized hiring a "competent man" — competency meant owning a car — at $100 per month through October. Funding shortfalls would delay real fieldwork until 1927.
1928 — Scientific Foundation
Major Joseph LePrince, the legendary Panama Canal sanitation engineer, visits Salt Lake City to review the district's progress. He insists on funding an entomological survey, warning trustees that without it, "your committee may be severely and justly criticized for working blindly." A young University of Utah graduate student named Don Rees is assigned to lead the field work.
The Rees Era
Don Merrill Rees became the catalyst for mosquito abatement in Utah. He earned his BS (1926) and Master's (1929) degrees from the University of Utah and his PhD from Stanford in 1937. From 1930 to 1937 he served as supervisor of the SLCMAD while teaching at the University of Utah. He joined the Board of Trustees in 1938 and remained for 39 years, until his death in 1979.
Rees was known as the "Father of Mosquito Abatement in Utah." Four of his University of Utah graduate students later served as president of the American Mosquito Control Association: Jay E. Graham (1966-67), Glen C. Collett (1972-73), David Bruce Francey (1976-77), and Lewis T. Nielsen (1977-78). Rees himself served as AMCA president in 1952 and received the AMCA Medal of Honor in 1973.
1927–1933 — Establishing Mosquitofish
The first attempt to establish Gambusia affinis mosquitofish in Utah came in 1927, when 50,000 fish arrived from California. They thrived through summer but none survived the winter. A second shipment in 1929 from West Virginia perished en route. In 1931, a third attempt finally took hold when twelve mosquitofish from Tennessee survived the journey. The fish were kept indoors over winter, then released the following spring. By 1934, a single warm spring pond near the city supported roughly 40,000 individuals, enough to seed populations across the valley.
1933 — Federal Partnership
The Civilian Works Administration assigned 1,000 men to mosquito control work in Utah. Rees personally supervised nearly half of them, ensuring drainage projects respected wildlife habitat — decades before integrated pest management became a formal concept.
1939 — Cooperation with Duck Clubs
Rees, a lifelong hunter and fisherman, hammered out a cooperative agreement with the fourteen private duck clubs along the east side of the Great Salt Lake. The plan, accepted by all parties, balanced waterfowl management with mosquito control on what he had identified a decade earlier as the region's primary breeding source.
Postwar Growth
1946 — A Home, of Sorts
One acre of land and a 600-square-foot former Army Air Corps signal shack were purchased as government surplus. Material shortages after WWII meant the vehicle storage and shop had to be built from surplus military ammunition crates. The chemical storage "building" was a container previously used for equine encephalitis surveillance at the Tooele Army Depot. Some of the original ammunition crate boards are displayed in the current facility as a reminder of those humble beginnings. This site served as headquarters until 1993.
1955 — Glen C. Collett Becomes Manager
Collett, who had earned his BS (1949) and MS (1951) at the University of Utah under Rees, returned from service as a medical entomologist in Korea to lead the district. He managed SLCMAD until 1987, then served eighteen additional years as Executive Director of the Utah Mosquito Abatement Association.
Mid-1960s — Ahead of Regulation
Collett, watching agricultural overuse erode DDT's efficacy and reading Silent Spring with concern, ended DDT applications years before the EPA banned it in 1972. He pivoted to ultra-low-volume cold aerosols and fixed-wing aircraft, and developed a hand-drawn paper-chart system mapping every known larval habitat in the district. This system of over 100 mimeographed maps laid the foundation for the GIS databases still in use today. Other Utah districts adopted the same approach.
1980s — Field Mobility
When three-wheel all-terrain vehicles became available, Collett adapted them for surveillance and control work in the wetlands surrounding the Great Salt Lake. ATVs became, and remain, the workhorse of Utah mosquito control.
The Modern District
1987 — Sammie Lee Dickson Becomes Manager
Dickson, a Lewis Nielsen student at the University of Utah, took over from Collett. The following year, he dropped all organophosphate larvicides and switched the district's primary larvicide to Bacillus thuringiensis israelensis (Bti) — a target-specific biological agent — well ahead of any regulatory pressure to do so. During his tenure he grew the budget from $282,000 to $3.5 million and the full-time staff from three to eight, including a biologist, GIS specialist, and dedicated field supervisors. Dickson served as president of AMCA in 2001 and received the AMCA Medal of Honor in 2012.
1993 — A Real Facility
A new 23,000-square-foot facility opened on a two-acre site, ending the ammunition-crate era. It included a concrete chemical storage building with double spill containment, indoor and outdoor mosquitofish-rearing spaces, a dedicated laboratory, an insectary, and on-site laundry and locker rooms designed to reduce employees' families' pesticide exposure.
2003 — West Nile Virus Arrives
Surveillance and control programs across the state were reorganized within a single season. Dickson launched a bicycle-based catch-basin treatment program targeting Culex pipiens in urban gutters and storm drains. The approach has since been adopted by other districts and private industry.
2013 — Migratory Bird Die-Off
An estimated 15,000 to 20,000 eared grebes died of West Nile virus on the Great Salt Lake — possibly the largest WNV-associated wild bird mortality event ever recorded. Bald eagles scavenging the carcasses were infected next; 82 died before spring. SLCMAD biologists co-authored the scientific account.
2014–2016 — Leadership Transition
Ary Faraji was recruited from Mercer County Mosquito Control in New Jersey as Assistant Manager in 2014. He worked alongside Dickson on a five-year expansion plan and became Executive Director on Dickson's retirement in 2016. Faraji was later elected President of the AMCA.
2019 — Current Headquarters
The current facility opened on 15 acres next to Salt Lake International Airport, with 62,000 square feet of building space. It includes an administration wing, training and conference room, vector surveillance laboratory, molecular laboratory, two insectaries, a four-room dormitory with attached laboratory for visiting researchers, two vehicle storage buildings (one each for the urban and rural programs), a pesticide storage facility, and an indoor fish hatchery. The conference room has served as the meeting space for the annual Utah Mosquito Abatement Association Spring Workshops.
2024 — Centennial
The district enters its second century with an annual budget of over $7 million, twelve full-time staff (including five PhDs), and forty to fifty seasonal employees and interns each summer, primarily students from local colleges. Phase II construction breaks ground at year's end on a heliport, hangar, jet fuel station, pesticide bioassay laboratory, adult bioassay cages, an additional laboratory and insectary, and larval bioassay vaults, adding 250,000 square feet to operations.
Innovations and Contributions
Throughout its history, SLCMAD has been at the forefront of mosquito control tools, methods, and products:
- The first established mosquitofish populations in Utah (1933), a practice later adopted by other Utah and regional districts.
- An entomological survey before action, establishing the principle of measuring before treating.
- Hand-drawn larval habitat maps that anticipated modern GIS.Early adoption of ultra-low-volume cold aerosol techniques and fixed-wing aircraft for mosquito control.
- Early adoption of Bti as the primary larvicide (1988), well ahead of regulatory pressure.
- The bicycle catch-basin treatment program for urban Culex pipiens control.
- Open-source 3D-printed surveillance equipment, including miniature CDC traps, gravid traps, blood-feeding devices, and dippers, with files freely available online.
- An indoor fish hatchery (2019) producing mosquitofish year-round under controlled conditions.
- An unmanned aerial systems program initiated in 2016, now including four drones.International field collaboration, including malaria control work in Mali in partnership with the University of Bamako and the Ouelessebougou Alliance.
- Participation in the Rockies and High Plains Vector-borne Diseases Center (RaHP VEC) led by Colorado State University.
- Host site for the Public Health Entomology for All (PHEFA) intern program funded by the Entomological Society of America and the CDC.
Looking Ahead
The challenges of the second century will not look like those of the first. Invasive species, emerging pathogens, urban densification, and a changing climate are reshaping what mosquito control means and where it has to happen. Genetic and molecular tools — sterile insect technique, CRISPR, Wolbachia, RIDL — will likely change daily operations within a generation. The district is already designing its bioassay capacity around them.
What will not change is the underlying commitment: to science, to careful stewardship of the wetland ecosystems we work in, and to the residents of the Salt Lake Valley who, on the warmest evenings of summer, can step outside without thinking about it.
