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  Town of Johnstown

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The Town of Johnstown’s Environmental Mosquito Management Program

Description: 2008 Proposed Johnstown MapIn 2014, The Town of Johnstown Mosquito Management Program completed its 11th year of cost effective Integrated Mosquito Management operations with Colorado Mosquito Control (CMC) as its contractor. Mosquitoes are dynamic insects which are capable of rapid populations increases dependent on habitat, water level, rainfall events, and temperature patterns.  The experience and knowledge possessed by CMC employees of the local lands and irrigation patterns, enables an overall reduction of mosquitoes.  The biorational management operations and data driven response to spikes in mosquito abundance are aimed at reducing the risk and annoyances associated with mosquitoes.  If left unmanaged residents residing throughout large sections of the town would be burdened by mosquitoes, thereby resulting in a decreased quality of life and reduced ability to enjoy outdoor activities.

The primary objective of the Johnstown Mosquito Management Program is to employ trained field biologists to suppress the development of larval mosquitoes in the aquatic habitats.  CMC prioritizes, at minimum 90% of resource allocation on larval control efforts. Surveillance monitoring of adult mosquito populations is performed to determine the need to reduce adult populations via adulticiding materials. This goal enables a reduction in both the overall mosquito populations and the threat of mosquito borne disease transmission at the least possible cost, while minimizing the impact on the people and natural environment.

Please call 970-962-2583 or 970-663-5697 to report any water that stands for more than 4 days, mosquito annoyance concerns, or for information regarding West Nile Virus prevention.

Service Area

The larval coverage area includes approximately 7.2 square miles of private and public lands, where resident contact has been made and permission has been granted in the town limits of Johnstown.


Please click here for the 2014 Annual Report for the Town of Johnstown.

Larval Mosquito Control

Johnstown’s Integrated Mosquito Management program focuses on utilizing naturally occurring soil bacteria, larvicides, to control mosquitoes in the larval stage, instead of relying entirely on application of pesticides in the form of fogging materials.  The program primarily utilizes applications of Bti, a stomach toxin, which is target-specific to larval mosquitoes. This naturally occurring bacteria is activated by a specific pH within the larval gut and disrupts the larvae’s ability to consume and digest food resources.

When properly carried out, by trained applicators, IPM programs return beneficial results in reduced pesticide use, reduced frequency of pesticide resistance, and reduced exposure to pesticides by the environment. The Mosquito Management Program offered by CMC follows successful IPM principles for cost effective, scientific methods of survey/inspection, evaluation, diagnosis, application and record keeping of materials used.

To date, there are 122 active larval mosquito habitats and 46 mandatory sites (weekly or twice/week inspections based on seasonal potential) included in the inspection and larviciding program for Johnstown. In 2014 Colorado Mosquito Control performed 352 larval site inspections, of which 281 sites (79.8%) were wet upon inspection and 150 (53.4%) were producing mosquito larvae in the Town of Johnstown. An estimated 172.8 million mosquito larvae were eliminated before emerging as biting adults via larvicide applications. CMC applied 593.4 lbs. of VectoBac (Bti), 21.1 lbs. of Vectolex (Bs), and 3.6 gallons of BVA mineral oil to 77.4 acres of lands in the Town of Johnstown.

2014 Surveillance Light Trap Data

6Information about mosquito abundance and species identity is critical to a successful mosquito control program.  Colorado Mosquito Control employs two kinds of traps to monitor mosquito populations.  The most commonly used is the CDC light trap which  uses carbon-dioxide from dry ice as bait to attract female mosquitoes seeking a blood meal from a breathing animal.  Once attracted by the CO2, the mosquitoes are lured by a small light to a fan that pulls them into a net for collection.  The Gravid Trap uses a tub of highly-organic water as bait to attract female mosquitoes that are looking for a place to lay their eggs.  A fan placed close to the water surface forces mosquitoes that come to the water into a collection net.  Once back in the laboratory, the contents of the trap nets are counted and identified by technicians trained to recognize the Colorado mosquito species.

In 2014, Colorado Mosquito Control monitored a statewide network of hundreds of weekly trap sites, collecting 505,697 adult mosquitoes that were counted and identified to species by the CMC Surveillance Laboratory. While individual traps provide only limited information, trap data is interpreted in the context of historical records for the same trap site, going back in time more than a decade. Ind7ividual traps are also compared to other traps from around the region that were set on the same night and therefore exposed to similar weather conditions. Technicians working in the Surveillance Laboratory at Colorado Mosquito Control are trained to provide accurate species-level identification of mosquito specimens, for both adults and larvae.

Additionally, the CMC Surveillance Laboratory conducts an intensive larval identification program with larval mosquito samples collected by I&L technicians prior to larviciding being identified to species.  This information is now invaluable in targeting mosquito control efforts as we gain a greater understanding of the habitat types preferred by Colorado mosquito species and the seasonality of these habitats as sites for mosquito development. 

In 2014, an average of 5 surveillance light traps monitored adult mosquito populations within the Town of Johnstown. Surveillance trapping began the week of June 3rd and full scale trapping was concluded on August 28th. There were 61 CDC light surveillance traps set during 2014 within the Town of Johnstown, which collected a total of 12,094 mosquitoes. There was an average of 198 mosquitoes caught per trap per night and an average 102 Culex mosquitoes per trap per night. The composition of mosquitoes collected was 51.3% (6,205) Culex spp., 48.2% (5,824) Aedes/ Ochlerotatus spp., and 0.5% (65) Culiseta spp mosquitoes.

Targeted Ultra-low Volume Adult Mosquito Control

The goal of Colorado Mosquito Control is to provide all residents of Johnstown with the best options for safe, effective, modern mosquito management. The primary emphasis of our mosquito management program is to control mosquitoes in the larval stage, using safe biological control products.  This environmentally focused program maintains adulticiding applications as a final resort when mosquito populations surpass nuisance or risk thresholds. Mosquito surveillance trapping results are used to make data-driven decisions regarding areas that need to be sprayed for adult mosquito control. Adult mosquito control spraying is targeted to specific sectors determined by this trap data, thereby reducing the area sprayed and the frequency of spraying in each sector. 

CMC uses all available data from CDC light traps, gravid traps, Mosquito Hotline annoyance calls, and field technician reports to focus adult mosquito control efforts on specific, very limited “targeted” areas. 

CMC uses state of the art technology, calibrated application timing, and least-toxic products to minimize non-target impacts.  All adult mosquito control is accomplished using Ultra Low Volume (ULV) fogging equipment and performed after dusk when the majority of mosquito species are most active.  This type of equipment produces droplets averaging 12 microns in diameter and allows for a minimal amount of product to be put into the environment. These treatments take place in the evening when mosquitoes are flying in greater numbers and non-target insect activity (for example, day-flying pollinators like bees) is greatly reduced.  Using this application technique, the overall goal of minimal environmental impact and effective adult control is achieved in the targeted area.

In 2014 CMC utilized the water-based product AquaLuer 20-20 in all fogging operations in the Town of Johnstown.  Colorado mosquito control performed 17.4 hours of mosquito adulticiding over 261.2 miles of roads in the Town of Johnstown, totaling 9,497.2 acres of lands.

Notification and Shutoff Services
Upon request, residents can be notified prior to spraying with Permethrin insecticides.  Call & Shutoff forms are available online and may be submitted via CMC website or by mail. Please note that a shutoff does not guarantee that drift of insecticide material will not occur and may decrease the effectiveness of adulticiding on mosquitoes in your immediate area. Please note that the call shutoff list is a service that CMC provides to residents and may be obsolete in the case of a West Nile Virus Public Health emergency, as experienced in 2003/ 2007.  For additional information regarding permethrin, including toxicology data please visit: and click on the tab for pesticides.