History of Control

The Warren County Mosquito Commission (Commission) was established by Warren County Freeholder Resolution on October 18, 1956. The first President of the Commission was Herman Shotwell from Blairstown. Work commenced in 1957 with a $2,000 budget. Throughout the first years of the Commission Dr. Daniel Jobbins, Dr. Lyle Hagmann and Dr. Bailey Pepper of Rutgers University provided assistance in the development of the mosquito control program in Warren County.

The Commission continues to perform its mandated functions with members appointed by the County Board of Commissioners. These individuals bring a variety of valuable perspectives and expertise to the Commission.

Mosquito Surveillance

Routine surveillance to document adult mosquito populations and guide control efforts was performed through NJ light trap collections coordinated and identified at Rutgers University, beginning with the first light trap placement in downtown Oxford in the summer of 1957. Light trap collections and larval surveillance were performed by Rutgers personnel until 1982. This work was taken over by the Commission with the establishment of a Surveillance Technician position in 1983. This position was changed to that of Biologist in 1985, later being modified to Entomologist in 1988. A high-powered microscope and illuminator were obtained through the State Mosquito Control Commission’s equipment use program in 1988 to facilitate the mosquito identifications. The Commission maintains a set of NJ light traps around the county for monitoring mosquito populations. The Commission contributes NJ light trap data on a real time basis to the NJ State Surveillance Program, which was re-established in 2003, prompting the addition of a Mosquito Identification Specialist position at the Commission in 2004.

Water Management

One of the initial goals of the Commission was to perform water management/source reduction projects to eliminate standing water that harbored mosquitoes. Work on the first water management project began in 1960 in Oxford, Cat Swamp. The Soil Conservation Service provided the engineering services for water management projects in the early years of the Commission. A contractor providing equipment and labor for $12/hour did the initial work in Cat Swamp. In 1969 the second most complete skeleton of a prehistoric elk ever found was unearthed during a water management project in Knowlton Township. The bones are housed in the Museum of Natural History in New York City and the finding was cited in the Journal of Vertebrate Paleontology¹. A part time equipment operator worked for the Commission in 1971. In 1980 the Commission hired its first fulltime heavy equipment operator while funding from the State Mosquito Control Commission (SMCC) provided heavy equipment to the Commission for this program along with funding for some individual projects.

In 1971, a part time Supervisor of Projects was hired through the US Emergency Employment Act as a part time supervisor of projects and then in 1972 became a fulltime employee (as Senior Inspector) in this capacity. This position evolved into the Executive Director/Superintendent title in 1977.

The US Endangered Species Act in 1973 heightened considerations for the protection of threatened plants and animals that could possibly exist in project areas. The NJ Flood Hazard Area Control Act in the 1970’s and the NJ Freshwater Wetlands Act of 1987 imposed permitting regulations on water management projects. The Federal Clean Water Act and related NJ Stormwater Regulation Program have imposed additional responsibilities regarding the Commission’s activities. Due to increasing permitting requirements, a part time position was dedicated to assisting with permit applications in 1998 and in 2000 the position became fulltime utilizing the new title, Wetlands Specialist, Mosquito Extermination (formerly Marsh Specialist) for the first time in the State of New Jersey. The Commission was instrumental in initiating the statewide Water Management Network to coordinate mosquito control workers in the state related to addressing source reduction and other water related issues. The Commission continues to maintain a viable water management program utilizing Geographic Information System (GIS) technology as well as Internet based aerial photography.


Since the Commission’s inception, it also worked to reduce adult mosquito populations with truck mounted thermal fogging equipment. The townships were billed for a portion of the cost for these adulticiding applications until 1987. Technology changed over time and the Commission began the use of ULV (ultra-low volume) spray applications for adult mosquito control in the late 1970’s. While part time staff performed this work initially, this practice ended in the late 1980’s and spraying for adult mosquitoes has since been performed by fulltime staff members, particularly the Inspector, a fulltime position established at the end of 1988. Adulticiding remains a minor but essential part of the Commission’s integrated mosquito control program.

Aerial Larviciding

In 1961 aerial treatment of large mosquito breeding areas for the control of larval mosquitoes was initiated with guidance from Rutgers University. The initial cost for this work was $1/acre. The NJ Division of Fish and Game set up caged trout in nearby streams to monitor non-target effects of treating the swamps. This program was discontinued in the early 1980’s but was then reestablished in early 1987. At that time the planning, inspection and coordination was fully undertaken by the Commission staff while the actual treatments continued to be performed by a contracted aerial applicator.

Ground Larviciding

Treatment of mosquito habitat for the control of immature mosquitoes began in the 1970’s on a limited basis. This became better organized in the 1987. Expansion of the staff to include seasonal employees beginning that same year allowed for a more comprehensive ground larviciding program. This progressed into well defined districts within the county with routes and site descriptions directing the field staff to the individual breeding sites within each district which greatly improved efficiency.

BioControl Program (Use of Predatory Fish)

Another means of controlling immature mosquitoes in water is the use of predatory fish. In 1990, a permit was obtained by the Warren County Mosquito Commission to stock an isolated body of water with Mosquitofish ( Gambusia affinis) which were obtained from a commercial hatchery in Nebraska. The fish provided excellent control and the fish population increased. In 1991, several thousand fish were harvested from this location by the state fisheries personnel and used to start the stock of Gambusia at the Charles O. Hayford Fish Hatchery in Hackettstown for the newly established State Biological Control Program (a cooperative effort between the State Mosquito Control Commission and the NJ Bureau of Freshwater Fisheries). Mosquitofish, as well as other species of fish used for mosquito control which are reared through this state program, are utilized at multiple sites throughout Warren County following established state protocol.

Mosquito-borne Disease Surveillance

In September 1998 the death of an exotic pheasant reared in Pohatcong Township marked the first recorded case of eastern equine encephalitis (EEE) in Warren County. In 1999, West Nile virus was first documented in the United States. The first evidence of West Nile virus in the county was documented in 1999 when a single crow tested positive for the disease. The disease has established itself and is expected to recur annually but since Warren County, as well as the rest of the counties in New Jersey, already have established mosquito control programs, the virus is kept under control. A comprehensive disease surveillance program, primarily for West Nile virus, began in 2000 with extensive sampling and testing of mosquitoes etc. and was enhanced in 2005 with the addition of in-house testing equipment for mosquito-borne viruses.

Public Education

Public education activities began in the 1970’s and became well developed with presentations to schools and civic groups, displays at fairs and other community events in the late 1980’s. This trend continues today with the development of educational materials such as unique fact sheets, fliers widely distributed through local newspapers, an upgraded educational display and slide show/PowerPoint presentation. Contributions were made by Warren County staff to Internet presence through state and national associations and with the establishment of the Commission’s own webpage in 2005. The Commission’s administrative secretary, a staff position that was initially part time starting in the 1970’s and becoming full time in 1990, works on the development and preparation of the various educational activities.

Field Studies

The beginning of the 21 st century began the pursuit of supplemental field studies related to the evaluation of various mosquito control insecticides, collection techniques and source reduction technologies etc. These studies are encouraged and are ongoing.


The Commission has been physically located in the Warren County “Carriage House”, the Court House Annex, County Engineer ‘s Office, the County Road Department headquarters (1985) and the County Road Garage building in Oxford (1988). In 1992, the Commission was moved to a new facility on the same county property on Furnace Street in Oxford.

¹ Variation in the antlers of North American Cervalces (Mammalia; Cervidae): Review of new and previously recorded specimens. Charles S. Churcher and John D. Pinsof, Journal of Vertebrate Paleontology, 1987, 7(4):373-397

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